AN I N T R O D U C T I O N
TO THE PHILOSOPHY OF COGNITIVE SCIENCE
Andy Clark vninniry of S-
NmYork Oxford OXFORD U N V lE R S m PRESS
2Wl
CONTENTS
~inmuarr viii
F?+e:Abur
A&nov&dpnrr
r
Remumr di Inndunion: (Not) Like lr R a k
I
1
M a t M a c k MinhnrrasSaftmre 7
r
SvmbolSyncmr ZE
3
P m m C o n m ~ m d G u m 43
4
Cammionism 62
I
Perception. Action. md the Bnin 84
6
Robots and AniGal Lie I03
@
h m r m i a 120
Technolow Byand the NsLcd Bnin 110
E
%hive
9
(Not Rally a) Conduaion 160 A ~ W D I XI %me &&drop:
Dualism. Bchrviorism,Funcliondisma d
W n d 162 A
~
I 11 XCoNciornnnr a d theMar-Hard Problem 171
-n bda 203
I89
ACKNOWLEDGMENTS
C b p t n 7. W o n 7.1. reprod-s N d oti@@ ~ -led m na p a p " T h c d ~ u n ~ d c h a i l m g e .I+,M ' I o m n 2 ! 0 , . 4 I I 4 R I . 1997, m d " ~ n m e and mtnd.' /arm1 afPntbsaphophl95(71. 3 Y 3 7 6 . 1998.
rom m a t i d horn "Ma6cWordr: H m hnr n s h u m m ramputation.' In P. G m t h m and 1. Bouchcr led$.). Lqwb md W g h t (Gmbtidgc, England: Cambridge U n i n n i v Pma, 1998).
Chsptcr 8 i n d u d n
~ h bao4 k grew our of r vrricty of undcrmdusw d u . uught in both ~ n g l m d end the United Ms.InEngltnbI un indebted msmdrnnand coUnguer in phi. brophy and in inhe r h w l o f Cagnitiwmd Computing Science. at the UniversiIy of suin the uni8.d States. I am indcbtcd to s m d m u m d coUraguer in Philaophy. in the ~ h i l o r o p h y ~ ~ o v i ~ ~ c cprogram, i P ~ ~ ~a hd oinIrhc ~ Hrwldf fishman MindlBrrin o r a m . dl rt Wshinaton Univrrriw in St. Lauir. Vviovr hicndr, m l l e a y ~ a d mentors, both 1the; institutions ;nd clwwherc, d e w m rrrvspcid . . thank. Thdr vim mdcritidrmr have helps3 rhapcevcrythingin fhia book (though, .r is customnry, t h y are nor to be b l s m d for the faulu and lapwsl. 1 ern thinking of (in no particular ordcr) h n i c l Dcnncn. Paul m d Pal Churchland. Mavrcr Boden, Brim G n M l l Smith. Tim Van Geldcr, Michael M o r r b Bill Bechtrl. Mirhncl Whcrlrc, David Chdmeri. Rick Grurh, Aaron Slomm. S v u n H u r l q , Pear Grmthnr lohn Haugeland. Isu P r i m Ron Chrisly, Brian KccI..,n, Chris e.a..& . . , md Manin Davis. I owe li sped drbr ts fiends and rd.~ .... P.. leagues worhne in ncurouiencr. robaticr, psychology, anift~irllilc, copilivc anth~opclogy,rconamirs, and beyond. espeidly David Van Erwn, Charls Andcmn. Douglsr Nonh. Ed Hutchins, Randy Beer, Borbm Webb, Lynn A n d m Sttin. Meja Matnric, Melanie MiahdI, David Cliff, Chrir Thorncon,Gther Thclen. Julie Rutkoraki. nnd Linda Smith. text irncw.but Ii w c h a p t e n d n * r o n m a t i d ham pubMort of thcpr-I liahcd articles Chapter 4. W o n 4.2 ('1, incorponta some m t r u from 7hewo*. the flcrh and the ~nificidneural ~ ~ o ~ ~ o k "a-pf po r in I. Ompbcll m d G. Olivrd ( c d ~ ) .hn.wsw Mind and Machina (Oxford. England: PIford Univrrsiw Pteu). a a p m 5. SIItion 5.1 ud aupm 8. 8.1. indude materid h o m W h e r e b"& body md world mu id^.' ~ a u l n l u s127(2). 257-2W. 1998. ~~~~
~~
~
-
won
Sincere t h a n k to thc cdilon and pub!irhm for pennirabn m urr thir mmid hm. Source oftigum w &red in the kp~dr. Thmh to Beth s~mebnm,T a m m G u n o n . K.thcMe McCabe. md Kimk l y Mount far m n l u b l c M p in preparing the m u u r i p t . Andto Lob,t h a t . for rining on it during aU 8 1 . g ~of production. T h a n k s a h t o ( j , a e G d u n . n d a bevyofanonynnurrfnmwhoumm. m m t s m d m&au hrumsdcan c n w m o v r & ~ n c c t o t k f i m pmdun ~ And findn e n t i a l l y , but so very inadcqurtely. UI.nlu +nd mearm m my wife and collcrpc, lowfr Toribio. and to my w n u . Chrk~inem d -1 Clrh .bd w , your 10% and -Won mcrnt the world.
Enddon-M1tcheh.l. D.,and !.chon, F. II9%1. %b#,yo/Mind
RESOURCES
mdr with rp&cih suggertionrfor further mding. Bur i t ir rb vonh ach highlighting o numbcr o f h i r rrmurra and rollenionr: khfd,W, md Cnham. F. (IWI.A Crm1"ion to C & t i x a Orlord, En&md: slrrkwll. I ~ l o p d " . @ e < n t . * . on dl the impomnl topi- 6 t h a uwful hmto"& i r m d u d o n by Whirl, Abnhlrnwn. and Gr8ham.l Phi1omphyofldfi"dl inrd1;pn. OIford Endand: Oxford Uni. &dm. M. (19901. m q ~rcu.( ~ r n i mpl p n hy T u r i w Slarlc, N-11 and Simon. and Man, with some nwrr m a ~ b l i o by n ~Dmnst. Dmi(u* and D&s. P.M. Chuwhhd. and ah.rr.1 M 11m96). 7 k R I h p h y o f A h f i & I M r d , England: 0 x b d Unirnnty ~~~... r r r(,~ r~ l r inuadwton r , e r u,r b ,. I m n o n . and a uwful windor on a m r n r l r d c btn in th'u a m . ) H m g h d , I.iL9971. M;hdU& I!.Gmbridgc, M I T Pm .. (Fanustic colLNon, inrluding. rm. inlrnd&" by H."%l."d; r m i n r l ppn b Turin& m n ~ l . Newdl and Sunon, Minsky. Or+ md Srarlr; r wmpnhcn.ive inlradurtian to ronnrrrionkrn i n papen by Rumdhan. Smolcn%kr,Churdlurd. Uormbrg, m d c1.h wmind c"tig.n by odor and 4 1 ~ , h p . -7, slich, and ~ a m nand ; r hint d n r w fmnd~rsfrom Brmlu and Van Gelds Wit. indispmsabk.l L p n , W. (LM) MmmdandCqn?MA . &R Clmbndp. Md: ~ l a & ~ ~IGral li. v.1~- larg. and r l l < h o w n mllntion r o n u m r ~ i n on g the n r i i r r d&c; m r funabndirm, in$tiummt.lism, diminsnrism. a d thc Ianguqc oithou8h*, rith "*dl vrllnn un .on* ,nme.<&"* gull 2. r u . . ~ ~ , ~ ~ ~ o . r ;1w1 anmanurn kbous.r k h k d FX. pamaon Orfod. ingland B l a ~ ' - ~ l I.A
-.
~
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-
~
LF
rn
uun..u
.
rabmb h m contrnu ih.1 nicrly mmplcmml the prrvnZ &ti* szirntiliulh orirnted, p n p e c t i v r :
T m r-r
andQpi&m Ollard. Enidand: B I = k l l . IwUmr inuodurm*l t a t <m.iq the maw l d i t l o d y p h b p M i u l rnt4to.l o l identity ~hmry,b d o n d i s r n . and debt- rbovf m n m r I.(19961. PhllarophyofMind Boulder. C D W s n i n . IA rmly crdlmn tat. rwsiq~hahmorism.i d o l t i n hmn, mxhule bnclionalurn, md d h e m abom mnviovrnnr and ron,m,.,
m.
l NTRODUCTION (Not) Like a Rock
H e ' s how lmyyy 21.2000 prnmd out for thm diRcrrnr c1-e unl order.
of the nat-
Elrmcnt r: A Rock
-
mc
H m is r day in the lib of a small. gny.uhii mck wrtling m i d s t kv, in my St. Louis b x b r d . It %Dyedput. Some things happened ta it: then wr nin, m d h bearm wet m d shim; then war *rind, and i t was subtly nod& rm u t chased a quinel nearby, m d this m s d the ~ mck %my.That's about it. really. Them ir no reason to believe the r x k had any ihoughu. or that any ofthir fck i i h anrhlng to Ihc m k . Stuff hrpptned. but that war all.
Elcmcni r A Cat lob, vut,had a rather difimnt kind o f d q . About&% ~f nwr rpnt. as usu.1. asleep. But there wcre Bny into the wking, widnvrorld. m n d 7 r u . some in. nrr stirring k d Lolo l o ail the house, making rtnigbtforth. u t R a p from Ihr warm pcmh of the living mom sofa. Outside, bodily functbnr dcmbflns domimwd. at Icsn n first, utc.. rollowing a brief vip back inside ( ~ ~ m i n grouted ly via the at. flap and thefood tray]. squirrels *re chased and dangnr avodrd. Othcr crO w r e d=altwilh in w y r rppmprialc to their rank, rhhon. bnh. m d meann.9~. Thenwas Igreat deal of funher sleeping.
Element 3:
Myself
-
me
My day vms (Imink) mher mom like Lolo's than lik rock's. we b ~ (Ldo h and I) pursued food and warmth. But mlr day ind&, IS u r p M . Rmcr m m o ~ g h t
mhp(mian.The kindof~plnlingmsriontcmplarion, infad,that has somulms goncn philomphy a bad name. Manin Amir caplured the spl'it wll: I timu mud thrilling wif.piv. ( l u h r ~ a that ~ vI up to nn?'IS.M. m w i a n g thl scl$rmgr~ubtiwM i n d his thoulht and the selfrnngr~lrtion behind that mognition, and the rdfanpfulation hhlnd rxognizingthat m c ~ "itb". sa*on. (wartin ~ m i r rha . R&I hp".p. 6)
Ia m i g did some ofthat. I had thougha, even 'trains ofthought" (reasonable rqucncer of thinkings such as "lrs 1 P.M. Time to c r t . ~ a t ' rin the fridge)' m d so on). But therewere also thovghr aboutthoughtr, n Isat back and obumrd my am trains of thought, aIm for mlorful exampla m impon inm this a.
W h ~ l , r h m . d ~ r l ~ n y ~ ~hh co smu ld a n d lpcrhaprlpnvln hnmul'wlnn are Lh.mc.hmsm thrr m.k,hough,.nd f~l,"gp<,,N.~A"d rh., hnhrr,n
-
.
I.The feelings that chanctnirc daily rrpmencc (hunger, irdner* desire, and m 0")
2. The flow of thougha m d w o n r 3. The mtu-flow of Lhaughaaboutthoughts [andthoughtsabout irrling.), of mflLmon on rrrronr end ro on.
Most of h e hc-rch p m p m s covmd in this t m have r o n r m t n t d on the middle option. They have uird to cipldn hmv my though8 that i t L IP.M. could kd fumy thought ibouc lunch, and how h muld cnuw my z u b r q u m I w ~ h weking a&ms. All hrcc mrs of phenomena are, ha-, the rubjra of whal philorophendl'mcnelirticdiu;ouru."A~iulsnmplcofmmtrlistt divaurw b the a p p d to brlieh (md deisr) to eiphin actions. The morc technical p h r w 'propxiriond anitudc prycholoa" highlights thc rlrnderd ahav of such cxplanations: such aplanslionr pir mental atlituds (klievin& hoping icaring, rtr.) with rpcific propositions ('that it i s mining.' .that the
Svchv.pefrper!d~giandthinkingipy huge divikn&Thcyrvppons rur. pKmgdegreof prrdictivc rmu,and arethemrnman r u m e y c f many of our wwhl and prsdicsl pmjeN. I n thisvein. ~ h c p h i l m p h m iny Fodor r u ~ e rhrt a cammonxnw psycholow ir ubiquitous rlmast inv%ibir(brrsuw i t work so well), and pm~riully;d;~pnxlblr. Far rumple. i t ensblrs w lo make p m i m plans on the bark of mmwne'~2-month-old statement that hey will arrive on flight 594 an Friday, Novembrr 20.1599. Such plms ohm work outtruly amacing fan rim ihc number o l o h n > u lnrisbles involued. Thcv work out lrhm ihcv do) &cruse the rlrrmrnt rrflms an intention (to arrive that by, w that flight1 thnl ir romchaw m active shapr of my behavior. Idrrirr that Ishould arrive on time. You know that Im deice. And on that bash with r little o o ~ n t i o nhem ihc wodd at 1% m i n r l n of coordination o n -r OI sr Fdor more coiorfu11y puU it
..
s y m want a h a h e r e my p h r j u l W y *111b.w n ~hunday,mmh.nictnur ~ Ydrnr. I of m i d k r k d obias *her 41, and w!dm hpmty 4in i u kldis "0 *Y t o p " r. di. Far fh. b s l m y lo E d om Ivrvllly in pnoi
-
.
.
t o l~.. d in m aonmnnltc wru) ,,..?.. .. ~
~
~
~
O n e upon a tame. p~hapr.81 would hrrr k n ~ o n a h l to r m p n d to the rhrllengc hy ciling. a IF 1 klnd of iptnn-~ubnancr.the 8mmaMal but uorallr r m m w d mt ofthr menl.1 lfor mmrcritml dtsruumn. m C h u t ~ h l m d 119811. . Pp. 7-22, i n d Appmdii Iof the p r m r trnl. Our con
MEAT MACHINES Mindware as Software
1.9 !
v.2
Sketches
'
-.......... r
I,%-." A-mrw,
Lml *1
NANE?
computer rcientin Manin Minsk once d f ud the human bnin rr a mcat machineno no Ins. I t is, lobc sure, an ugly phnse. Bur it i s slso r sniWng image. s compacl expnaion
ofbath the gcnuinc scientific excitement and the ralhcr png-ho matclidism that tcndcd to char aacnrc fhc early year$ of mgnitive scimtifir r c O. COrn-~nn* ~ n h w a nand . ffsl rnrch. Mindwa-ur thoughts.fmIiny, h o p . fnn. Mi* and i n t r l l r r c i s ra* as nothing hut 9.3 A ~ i r n i a thcopen!ionofihcbiola#cal brin,thr meat mr< J S u g n n d Rsadings chine in our hnd. Thi, notion of thc hrnin i r r m a t makineis intmting.for it immrdialrlyin. v i t a ur to h K ~ not r so much on the mawrial (the mcatl as on the machine: Ihe w y ihc material is organizrdmd the kindsofopention it ruppons. Theramcmachine (M BOX1.1) an. afim ell, ohrn he made of imn, or accl, or tunsslrn. or whotcvcr. What m conhnt ir thus both r re,-tion of the idea of mind as im. material apirit~ruffand an affirmation that mind is k t studied fmm a kind of mginrrring pmpmivc lhat meals the nature d !he m r h i n r t h r a l l that mt. white. gny, a d rlicky rtua happens lo build. What cuclly is mnnt by carting thc bnin ar s mxhine, nlbeil one made out of m n t ? Thcrc rxilts a hivtorir.1 rrmd, to be sure. d mine " to understnnd the workings orthe brain by analogy wirh variour currently fashionabk technologin; thctdcgnph. !he r t n m endnr. m d the trlcphonr swicrhbaardarc ell u i d to have had l h c i i a y i n the sun. ~ l v ihc t "mnf machine" phnrc ir inlendrd, it should n a bc clear, to da more than him at romc mugh analogy For with rqard to the very r e a l ~lru of m c h i n n knom ts cornpurcm. the dsim is that the bnin l a d . by M,,,M
-M
nnd b h ~ r w
I
I
.
I
10
CHI\PTER
8
I
MEAT MACHINES
SYNTAX A N D SEMANTICS
phrrri rmd to uw th. tmn irr noacmnrr prot rs,winen m *o& or of m y Endl of invriptions of mranhwid itnnr (r*. tbr math.t the &rn ulcuittar-to stare anurnbe in mnmvl. TM wonymow urinrn mrds ("W .nd "dzichirn-1 tbvr -W i k n t i a l but sp1tutir.1Iy d'inina. whmbiguaur uo* (W u in rirn or am);- rr in hi& NM) ur nlntl"icaUl idrnnhl but novlljany idn oft rprriik tcrmutrdr iton (q. hir dinion Theidea of n f o h ir ocrurrcnccof lhe word "dot?). A v k e ul&tor mmlpultc. ph* lo-
ibl computer, introduced the fouad.tion.1 notion of l h t has since come to k Lnmm 151 rhc Turing muhinc. This ir m imagimy d d n conds~ingofan infi. nitc irpc, asimplc praruor (1 "finitr stat= machine"). m d a m d l w i t r herd.'% t a p iru u data stare, using ramc furd XI of symbols. The r a d l m i l e h n d o n md. symbol ofithetlpt, mmmr irwifonr squm backwad or fomrndon thelap?. and witconto the t a p . Thc bit, starc machine (a Wnd of cattrrl pmcamr) h u cnou& mcmov lo null wha symbol ws jvst m d and wha state it (@he finite state machine) mr in. Thnr h*o frru togeher d c l m i n c thc n d adion. d i c h ir carrid out by rhc mdlwritc herd. rind demminc dm Ulc ne* rmtc of rh.finite n#< machime. Whr Turing show4 wrr that some such device, prfarming a rcqurncrofrimplrmmputarionrgovtmdhythesp~~bakon thctap, muidcornpule rhc mswcr to m y ~ ~ f f i c i r nwcll.spccificd !!~ ~mblrm 1e . Box 1.3). Wclhusconhont a quircmarvclaurconflucnccofidas.Turing'swork
...
me sum e l n w lnrl of malpis, in+ndmt of p h p h irt mrrhani~ir in spirit. . . a wime of unrmre and hnniondivonrd fmm mrfnid ~ u b r t s n a (4hrhy. 1986. p. MI
are thv. firrt-mt, nnmpla offand mmnr in the umr o f Hmgdmd 8: (lmla, 1997). ~ h arcq s w m s ~ h o r e w e iinnor in rhrprcciw phpiral &mils but in Ulr wrb of legalmwcr and ,nnritions. M m @ma. H ~ ~ g d notes. ~ n d are formal rplcmr in n r d y this cow. YOU chess on r h r d o f w d or mrrblc, uring pirur alupcd lilv s n h r l ~ cm movie sun, or the c r w of the star ship Entcrprirc. You could even. H a u s l a d %uwn~s, play chn. uing h d i c o p m 83 piem and 1 grid of helipad. on top of bll buildings i s the hrurd. AIIchat malten ir w i n the web of kg21 moves and thr phpical distinguihibilily of rhr tokenm. w r p rt 'ninliing about formal sptrms thur iibcrr~erun in r w wry ~ ~ r o ksemmric c. rrbti~nr( ~ c as h truth pm"emtion: if"A and 8" i s t r u r a "A" is IN?) arc Y C to ~ be IIP~L~~ in virtue of procdurn that m a k no inhinsic refncncc to mnning. ~ n the d ~ p r c i fphyriul i~ d a i k of m y such sptem are rn lo bc unimpmnr. since what mattes h the golden web of moves and imriginnr. %anria is Bur madc ~nm)rn.riour vnthavt m&ing it hruur phynicrl. Who s a you ~ cm't hare your c l k r and cat il? n c n m b i g d o . ~ . ) o wsr ~ ~ the f formaliution (Turing 1936) of the notion of
Thw xrrdrrsilll
Of c a m , ihc mdzinr n d a a p m p m . And pmgnml were, i n lhov &p (but arr Chapter 41. m i n m by gmd old-faxhiand human b c i n g 8 1 once the pmwarn war i n place, end thcpwer on, thr machine took ram of ihc mt. The tnnsitionr bchcn 1-1 synwic lutes (states lhrt a b , under inmprclation, mmnr wmlthingl nolongcr rcquiml rhumsn o p r r t o r . n e p h p i u l ~ r l d ~ d d in^ ~ n h d u d d d~11,nonevoIvd,nonorgrnic r m p l n o f w h a t Vanicl Dcnnnt would latn dub 'wladic cngini'-gu=siau~onomou~ iplm who= ahrcr phrsid m&e-
CWAP~ER 1
12
I
MEAT MACHINES
lharthuwmvld &-named u n i d Turing rnwhine) chine. The m b d r on the up. in rtur or ilr W a v i n or the ahu m*rhioe. thii devription to mLllic thr inputc and h c c ir iuclf capable d u r hdh 1995; H*ogLnd, 1985; Turin& 19%, 1950.) Ihr Turing d m * r l f d r fmnc-el of a simple car in *hi&
1.1.A nt.1 p w m for adding th ti.l lmtition end i n i a state of th
x "A A'indknl d l bas follori:
Uurmaiaa I:Bmd-mite had i
te A end mcovr
quucfothc"w,,,
m",.
ins) pmoa N m dx, that you mdd bultd @ simple Turing ms&c out o f w m t m a 1 4 & . Itirthch,no.l I~pnbcli~I orpiationthatrmt-
un for iaxrmstic NFcerr
<.,s,.. .d+inst.tr.
--
,hc k d i in A rncauntm. -+.tar in nnr A, m d moves one aqvarr to thr ri$ It. the k d ia in mtc A md it mcountm a .i,'
n rrplaca ir
,
up ensured (under intrrprrtalionl romc kind of ongoing rrrron~rrspming& hanor. No rondcr thc rarly rerern.herswere jubilanl! Nrwell and Smon capture the mmd:
n d go mfo numine Ntr 0.
.
ir not my lim to surprir a 8 - k w... . But Ur rimplnt %y l<.n~ n v n a r i u ir to ryfh.1 thoc ur now in fhrwald m d m n that bink. that 1and ,ha, o~
lnmunioo I: If the head ir in m it, *m with "a," end hr
1,
ate. Mor.com, thdr ability 10 do thcr &hei s p i n g to inmau npidlyvnBCln r ririhle futurcthe range ofpmblemr they can handlr *iU b. c-rnrnrirr G t h thr M g c 80 rhid the human mind has k n rpplid. (NlwU md Simon. IRB. p. 6 q m l d in Dr+s nnd D & 1990, p. 3121
. ...-hinc starts ahovld bt &I. to scc how "pint&- at the l&mmt"~.' l t sun.r@t %eking a 'c,' which ir repha with ~"1.. I t continuer canning xight until thc 'r" indicate ihc md of the sum, at hi& p i n t it m o m one Igvue left, d p!xe 1% with a "a," The tap mdisplayr the a lem in the u m c nontion urd to encod. the ql
YOU
s i r m-, ddiation, a d I
lhir jubilant m m d d ~ p c n c dIS a d w d pmgramming tcFhnigud brought
fonh impMivc problnn-ralving displays, whir the bmadcr thcomiui and philorophiul impiicalionr Iwe Box 1.4) d t h r u early rucrcrws could hardly haw brrn
aion,mulmo* rtrb-
I
more f i n s . Thc oncc-m,~t-ur malm of mindwm (rrpr-ted, admincdly, by jual two ofirr many d m i m tmlh p-mtion and abstract pmhkm rolvingl looked tipr for mnqurn m d understanding. Mind wu not ghody s t u t hut the opntion afa formal, rampdational ryncm implemen~edin ihc mcrnnrr of the brain. Such 3% the h n n olthr matter Mindwn. 81 w a claamrd, u to thenrural meat mxhlnc rr w l w w u to !he compute, Thc bran may bt the standard (lual. nnhly. hmdq~rl) 1mficmmut8on--butcognltun ~ r y ~ o . m . l k v!hang d Usnd
CHAPTER
,4
...
I
/ MEAT MACHINES
MACHINE FUNCTIONALISM .,.. ,
:
is thus &ortlyenaugh to float fairly free of the p y neu&nti& d&. But it i e not so &only .s to sop the o n . of mom rbsuut (fonnal. compaationai) u i m t i k invatigation. This h m spp.ling story. But h il c a d ! Ma w a r y ,
.. ... ,.
The h@'phhlapbial % o!ng p ir of thc dmlopmentr hutifidsl bldigeme weat by the nsm of machine fundonolirm, and it xu o f i d u .n anto one of the dquations mt asked by humankind, "r what bthcnunce (thcdep naum) of the mmml?What hdrm=nul frnr mk it t h e w t h a t some pans of thc p h p i u l w r l d heue mmtd liw (Ihoughtr kli4 feline and d rhc re*) and othen do nor? Subsme dud*, reuU, thought thrrt the lnnnlay in the pr-cc or rbwnc, of r tpcrial kind of mental ~ m f -ing i again* this id- ( a d sgainn rc-rsUd philosophiul hhevionsmA p p n d i I). Minbhrain identity theorin,, such u sman (1959) (end =grin,s e Appndix 11, daimrd that m a u l r t r t u j u n a n pracgoing on in the bnm. Thk bald identity claim, hawcver, thrcrtrndtonukcthrlmkbawrrn m m t r l n a t n a n d r ~ f i c materid , bninrtata a little rm intimate. A kcy10rry(~.&. Punum. 1960. 1x7) wu that i f 1% XU dy-,ial toMnginaremininmentdatatcthrtonsk inrrpedfic brain date, itwould srrm to follovth~tcrnturn lsckbgbninsbuilt iurt lik a m (sry,Mutianiior rilican-bracdmbot.1 could not hc in h w r m u m r mma1 saws. but the i n t u i h n wnt, c m r u m 46 wry diffcm-I b N N fmm o w could, at 1-n in principle, h e , c.g., th.bclicfthat it i. rdoing whoc. ,ha, should vx look for the mmmondity that muld unite thc nr bot. the Mart"n. end tb. Boaonim?Tbc work in logic m d f o m l ~ e m r T ~ r i n g m a & ~andcl~lronicromputltionnow ruggaud mnmwcr Ink not to the ~ ~ ~ i f story i ~( ~muronr f .ad wtwarrl, nor to ?he5°C-
Iru khanor, but tothe imer organization, thrt is lo rry, tothe p l d m wb:
+.
of the It b thh o W h " o n - drpicrd by L c machinefvnsnonalilr u swcb o f l i n k b y m parriblc inputs, inn- mmpuraliand state* m d output, (anions i~h!-that fim the ahap and confens of a mmtal life. building mtrrMr do not mar,.t ch. web of oamitionsould be &rd in 8.6, silicon, or cram ch(pumam, 1975, p. 2%). TO hc in such a.ndsuL a mmtrl a t = ~ * is rimply to h a phpical device, ofwhatrvcr mmpitioo, thm rtidrfin aIpcific formal dacripion. ~ h hinn hums, happm to run m a m a t machine. But the very rrm m h & m (.a p i d d out by rhr w b of 1 4 m* mnririona) might run iname rilimn drvice, or i n the dien organic mane, of e M.*iUI. lo fhc a h m r a formal rnglniutian
nc
*. WHY T l l U T MOUGHT AS COMWI'ATION? Why k t thought I.mmpuution?The primcipnl r-n (nprtfmm thc k a that it rrnu to wrk!) irthatthmkers m p h r j u l drvicrr whav k h n i o r panem m maon rnprting, Thinkm art in that ire d U y undcntwd r sensitively guided by mwn$ idea%m d hdich. Elmmnir computing devices show us one m y i n which thir nnnge "dm1 pmidd (of phyxical rubamce nnd mmnrcrprcthg bchaviarl u n irtullly come b u r Thc notion of -on-mpsring kh~vior,h m r m , b a n immediate mplifiution.Aniccumplcofthir WndofkhaviariagjvmbyZmon P$yshyn.Qylphp (1986) dwribesthcuv ofthe p4atri.n r h o witnnvr r crr cruh, runstoa tclcohonc. a d ounchn out 911. WE could. PS PYIvshw note. m to emlain this bc. ~ h ~story t (mayb, d i n v o l ~ r+c g neuron,, or -0 havior by 1 quantum evenu, whatmrl. But such a story, Fylyshynegua, will no, helpusundcntrnd thc khmior in its - n - p i d d a r p d s . For cxrmpl4 I u p p w m irk what would h s p p if ihc phonc vrr dead, or i f it ma a did phone inrlnd of a touch-cone phone, or if the sccidcnt m u d in England i m t u d of the U n i t d Stam?% nrural story underlyingthe b h a n o r ~msponscwill l differ widely if the rgrnt dials 999 (the oncrgmnq code in Englsndl m d not 911, or mun run to find Y e mmmon Mse py
. . .
., .
.
.
,&
..
..
.
CYAPTER I
16
I
MEAT MACHINES
is mining" I d a to the thought " i d s go indoors." This, for Fcdodor (but rrr Uup t m r onward), ir the rune of h m n ratiandiv. How is ~ v c h~ t i o d m qc chrnically pmribld A g o d cmpitical h w t h a i r . Fadar -a, ir that thcmut "cud (inn" rates apt for intoprelalion) h t man, rg., "it ir mining" and who. p h y t i d propenb lead i n m n t m to & gemration of other v b a l s that mean "ler't go indoon: l f that is how the brrin rm*r lhol the brain ir indeed s computer in nenly the wnx displayed arlier. And i f such m c the cuc. then thc myrtely
*C
.hit,
..
mind u a xnf of mpum, n begm to u.h a . dnm 4 k nonmnunt-rcl.ion. among odh/n l a l d *o+u ~Podo~odo,19S7, p. 19)
Sud,arguments aim to show that the mind m v t h u n d m t d u a kind of mmputn implmtnted in the v r ~ of rthe ~bmin, on pain of hiling r m p i r i 4 to acmunt far rational mnritialu smangthoughu. W n - g u i d e d action, it Y C ~ Z make good ulntific m w i f wc imagine r n e u d =onomy o w n i d ar s ryntudriven aaginc that tnck L e shspc of xmanric wcc(M, c.8.. f d o b 8987. pp. 19-20). B. E Y ) W A R 8 AN AUIOWOMOUS L
~+lsb-*hm
ir 8 -bk m m n u mn-ing wh* I'U dub & % s i c pm&" rh*hiswc0 q d b, the f o b w h g statemk *monrmabLUl~mnpvabrrnw,udaalr~bm,hhpwludout. PM k md manu=+ i n q m r d u rrprrmdng. . 6 ordd pun ol am. h*" bl in,la E b A d uld Somnti. 199% P. 651 ThweoasidrrrpoMd
mputa, on FI of info-
M L IN NANRE!
The mindwaml~ftwrcequation ir u b w i l i n g u it iS at time%dinortiul.
One immcdiatc m n ~ r r n i a hatau thin rmphria on slgotilhms aymbab and pro-s rmds to promote a rornwhat midcading\isian of nirp imldirtinnianr in n a t u n The impact of rhc th.aresid independenceof algorithm* hom hrrdwre k m arlifaa of the iong-tern n d m of irrucr concerning d - w o r l d *ion taking ud the 6 m c coum ofmmpulationb Fur an .lgaithrn or pmgrrm as avch is jun a uguence of stwith no inbuilt rdaion to ml-world timink Such timing depndr crudally on the pmiollar w y i n whiB the algorithm is impimeted on a real drvicc. Gim this bsrr 0,rhc thcorctial independmuofalgo~thmfrom hadnar is unlikelyto haw made much of m impart on Nature. We must <* to find bid-ui mmpuntionri nntegie closely tailor& lo geIIing usful rd-rime r s d t r from m b b l c , slow, w-rc compnns. I n practice, it is chvr unlikely ,hat m wiu be rblc to fuly rppmiarc th. formal organiu!ian of narurnl v I r m l without s m e quite derailed m e to the natured the ncvnl hardnare that pmvidnthr ruppning implementation.I"gmcnl, rttcfcntionto the nrturcaf real biolodul hardnarc l o o k l&dy to provide both imp-r due ahout and eon~ t n i n on u the kinds of compvmion.l s ~ wcd by ~ red brrina. ~ #This lapir ~ is ~ r p l o in d more depth in Chaptm 4 through 6. Funhmnore, rhcdaim that mindwre i s ramnrr i-louychckur-m+ mhematic. ror rhr s p . ~ of parib!, t y of ~~ I a m o s vw.PU bms* mmpu~ational(but BOX 1.5). is hrgr indeed. The m m m m r by F d o r m d by
--
~hnvrlhvrmrt thus fmcs I m rcmect numrmnnud conrrmnt.
tbr inputs a ~ u h '4 x 3- h d to o u t p i mch a "12. and so on A trvv d u a n d o n of the condition. und" which romc m d phc mromoa mbnm u mmput.tional vouM mlvi*. howmr. -me nthn momebjaiwoirnian for dncrminingwhrnmmrovnt.rrd(nondni&) p h W pis impismrnting a unnpuutio-mc criterion that k M pkts(= I OY infcIpmim activiticr and intcrcr. so firmbat renter 8°C. ~~
Thchar~. Ier 9). m m e "
nvofkdocmfi
m -obi&
u
~~
~
!%, Chsp rmmting a
ch.bnn'pmpad,inamczisthn~phpidd.*icrimpl-um lharr bm4l c k d p l h i * W o t i o o oflrsru d .r.r.-usadtim, n U) ina in mr "hm u 4 rtlvclurr of thr mrm mirron the f o n d
CHAPTER 1
3%
~haqesin rhe ph*
M
e ono the 4-e
u.~brmnsp-ih~. ch.lm.r3rah-
MEAT MACHINES
m d m i 6 a n r p r m a t in
ihd m y p h p i u l rpNm wU1 ;mplrmmt aamr m m p & b m l dwtiprion. But the ~ p p a ta l fhc-~cd is munt to m u r e t h n PY
MOO(
intappa ewyph73iC.l Wnn
u impkmrotingoaywmpum6aoal dacrip~ho.So.Lthoughtheclaim that Ule bnin implmmusome compuutional dnniption Y f d y uivial. the dsim tku it ~mpkmeo& a rpo@rnmpuuddrul dacription Y not. Aad i t 1 h tbr bnin'l i m p h m a t i o n of a qxcific mmpumtiaml d=%~@oi n thlt Y m u n l m q b h m m w pmpniof morr hmllhrdniarir, o f m e , Ihe rrlk m m p u a t i o d 4 1 d thc &libme impaaitaa of I mapping vi. wme p m of ~invUigmt dsign. But fixn a m t is not im.insia&ra mhaed. Thus supra,--bu.MorpmcLmerwtuthrxptncntm*ncrrofrd.ptiw imp-e sudr a tbr t k . number, and s p d of 8-ch of Vedat o n l f h t mldmuqp m a a rnulu in a p h N d yzcm wha. aud ~trt~iti~~~~~doUutinmpmtionM (e.g,iffwn l;e~ntic~ thm t w prrd.tor.dnmad r Ztud and fight* i n n o t o h ladingm o v t p ~hduvior, t x h ~three s or m m t W d r 'run and hide" re~pom), d m t i a m has. on Sir account, c * o l ~ d d computer. The brain, i f thc mnjmurrr w a v t d nrta pmv. wrrm, Y juS such 1 MNN~ mmpum. brpor.ting innn mta that q r - l m e m l m t r lruch rr the ~ e o f o r d ~ u r rand r ) + i t i n g ~ r r m n s i t i o n mutin- that m* w i b k e of& infomution thus mcodod
*
kind of ~0mput8tionalstov lone
Pylyshym do. it istru.. rugget 8 rather pvrrurd in derailin the next chrptcrl. Bur ihc bare nplanarory schema, in which semantic patterns rmcrge from on underlying $yfnnic, cnmpvtarionrl orpniurion wxrs a ~t~geriningly wide range of
Mest Machine,
'9
w d . a single doice may bc d q i c t d r.arriing ant r romplex p d c l m c h or as tnnrfonningan input r into an oumt y. Clearly. what gmin we rhwill be determind by what qumiona we h a p to m-r. Seeing fhr m n r i ~ i o n u involving a nured r p d c of padnlli anrrh may help uplrin apccific ermr pm61er or why certain pmblrmt nh longer to mlv. then athen yet w i n g rhr prar a simple vnsuucturd tran~formationof I to y may bc the bm rhoice for undemandingthe larger r u l e o r m i a t i o n of the w r m . Thm vill thw he a connmt intcnnion b c w m our choir. of nptarutory urgcu m d our choice of gain and 1-1 of ~~mputatianal dcrription. I n g n d . t h m smns littlc mvln to m p r a single tW( O t lee1 of detctiption to do all the work we quire. hplaining the relative rprcd at whth wc ralvc dilfnent prohlcms, m d the kind.of i n a d m u rffmr we r x p r k n u when tying lo mlvc 1pmblm~ at on(c-&. xmemkring nro closrly rimilsr telephone numbcn), may well q i r r nplanations that involve wry rpccific dnriii about how inn- rcprrunration$ i x $ l o r d 2nd srrucfund,whcr~ mcrclyarrounlingfor, r.&.the ham facts about R. tionrl tnnritions bc-n content-rclrtd though- may xquirc only r rg n i n d computational glm. [It is for p m i v l y this -n thar mnnmionirrr (ur Chaptol) dewribbc thcmwlvrr a crploring the mi
I&
C. MIMICKING, HODUJNC., AND BM*YIOP.
Gmputrr programs, i t oRm w m s oU'only.haUrm and brittle rimubmms of Be kind of understandingthat humans (md auhcr mimrlsl manage to display. Are t h m jw tmhing troubles, or do the -Id rhonhlk indlatc some fmdamentll problm with ihc romputationd approach it(YIR The w o w i s a g a d ""L. T hm u c . alas, all la, mmy wyl in v h i d a k e n camp"," p-m may merely mimic. but not iliuminatr, various ism dour mental life There is. for clrmplr a rymbolic A.I. program that d m s v n y fine N h of mimicking the mha1 rerponM of a whllophrcnic. The p m g r m ('PARRY," Colh~,1975; Radrn. 1977, Olapfn 51 user itickruch a wonohginput r n t n r r a lor kqwords (such as "mother") and raponding with canned, defensive outbum. I t is -pahlc, at r i m s of fwiing apnienccd p r ~ h w n a l p n But . no one would daim Uut
-
CHAPTER r
zo
MEAT MACMINES
it b@urerulpwrhol~cnlmoddofpmddicbimphrcni..~tillleuthrtit blwhrn up a d running on a compuar) s paranoidwhiraphmic itrdt! Or conridcr a chnr computer such as D e p Blue. hcp Blue, drhough aprb l e dwtnsndingphy, rclin hnvilyon the brute-forcet ~ h n i q u c of wing iu suprfM computing wwto ouminc d potential ouaomn for up to wvcn movn ahnd. his strategy di&n marltedly hom that of human grndmartm who scrm m rely much morcon smrd h o w ( d p and rUcd ptm -nilion (seeChapter I ) . Ya, v i w d hom z certain hdght. Dmp Blue is not s bad simulslion of human chess competence. hrp Blue and the hvman pndmasler are, after aU, more liliely to ag.. on a pmcular move (8s a r a p n r lo s given baud rut.) than nrr the human gmdmmsar m d the human novice! At the level ofgrau input-outpuf profilcs. the human grandmsaer m d Deep Bluearcthus rlnrlyrimilu(not idmticd, rr the diffcrmrc in underlyingnnrcgy--brur force vrrsuaprC tern rccngnition--vrmnimcr shine rhro~gh).Ycr once w i n . it is hard to avoid the impressionthat all that ihc machine i s $chimingis top-lml mimicking lhal there is ~ ~ m c t hamia i n ~ with the underlying s l n l g l h a t either rcndcrs it unfil a eubnrsc for C-I int.~~igmcc,or dw r c ~ n l rit aa a lrinn of intdiigmmcc v m slim to our m. is i m p m n f For we mun k arcful to distinguish the querThis la* tion of whether such and such r p q m m r o ~ i t u t e r g d mod4 of humn intelligencefrom the quatian or whclhrr thc pmgsm (when up and running) diiplay, romc kind ofrml, but prhopr nonhummn h r m ofintrlligcne m d undcrsanding. PARRY m d Deep Blue, one frek h i on b n h counrr. Clearly, mithcr mnrtilu!cr a hirhful orvcholodul model of the inner rate that underlie human ....~ prfoma-. And rnethingabaut the basic style of h e two computation~l vrlurions(ranned~ntmcnactimtdbykeywr&,md brua-forcclwk-shod) rum maker u unosywith thc (ullnmmiw
~
..
a.
MI*, Lluhim.
mate!). nor m k m omclcrt.. PARRY m n n d ~ i d to c h r r h m i t or ukr up the harmoniu. and vr on. This move to behavior is not without iu mn pmbkmr m d d.nges, as w will inchantn ~ should now bc d n r m why reme influentid theoriru - ~ ~ I - B U it (nprcidly Turing, 1950) argued rhsr r rufScirnt d g r e of k h r v i o d r v c m should bc d o 4 to wttlc the irsvc and to ntablirh once m d far all thst r andidaresyrrm i s a g m u i n ~ t h i n L ~ ~ ( d k i t o n ~ w h w c i n n ~ r wmaydifferptly o*my from our om). Turing propard r t a t (now known u rhr Turing Tat1 that inv o i d a human harmgator tryingto spot (ham verbal rerpnw.) whnhn a hidden canwcsnnt w~s humm or 8 nuchine. ~ n n(r1.m y capable of fwling the inrmogatar in ongoing, opcn-ended canrcrratian, Turing prop&. should bc countrd ar an inhlligcnt agmt. Su*uttiind, top-lnel*nbrl khsvior, ifthir h right. is. rvffickntt n t far the prrwnre of rslintclligma The Turing Tar invite conridrnlinn o f a wealth of i s v n that wc unnot d n U on hem I s m m i surface in chapter 31. It may bc, for nsmplr that Turing's origind rmriction to 8 vcrbd t a t leave tm much m p c far 'tricks and B o u * and that r &tar tm would to. cus mom heavily on real-world x t i v i ~ y(ucHamad. 19941. I t thus m a i n s unciar whder werhauld allow that ~urfrrebehaviors (hawcmrompln) nresufficimt todi.tinguirh(ky~ndsUthwmialdoubtl raal*le g fmm mere mimicry. Pranidly ~ p * " g . how-., it wcms I- monlly dmgemus to d o w k h a v i o d pmfilrr to lead thc way (ima$nc that it ir d i m e n d that you and you alone havc r muunr brain that uses brua-form, hcp Blur-like snsrmin w h m others urr ovitc dihnent tcchniaua: h u rdmce d'-wld that you nre nor r conwiour, thin!&& ruvrning k i n g aftn all!). ~~~
~~~
~~
-~~
-
~~~~~
~
~
~
.
D. CONSCIOVSW~, mm-TION. W D PIM -Ifone had to d-ribc
~
thedmwt mni*ntian for mtcrialiam, one might m). that it ir r tnmr of conxiownru" (Snrlr 1992, p. 551. Oh dnr. I f 1 had my way, Iwould give i n to the ernor m d just not mention row&ulneuet d.But it ir wonh a word or IMnow (md M Appendir 11) for two -nx One i a k s u w it is dl too n v t o see the hnr about ronwiow apcriene (the 'second upm of the problem of mindfulnc.." d n r r i h d in the Innoduaion) rr mnnituting r knd.dorn ~ c f u t ~oftthe i ~nmngecn ~ venion of the compuutiondil hypothe6%. The nher is bruurc conridention oflhnc h e help to hi@&, imprlrnt diffcnntnkbven infomarionaland"m~m~phyrid"phmomcna. SO hrregm. How could r d m e msdc of silicon k canuious! HOW could it 1-1 pain. joy, fear, plrrrurc. and foreboding?I t certainly mmr unlikely h a t SUB notic caprci t i n should flourish in such an vnurval (rilimnl setting. But r mommr'r ICOK
CHAPTER
22
I
/ MEAT MACHINES
w r e n n s on this plrnct ore curs of ranuiouann. in c a r b o n - w a w k lifc forms But this he is rcndmd wmmhat l e r imprrsivc once xr m l i that all n n h l y lilt forms sharer common chemical ancesq m d l i n n of d-nt. I n sny src,the guntioh at Inn.I h r as uhc central thesis of the p-t i s concerned, ir not whnhcr our l o u l carbon-bad ergnic r u u c t w ir crucial to dl pomiblcvcaionr o f ~ o n n a uavucnru r (though i t sounds mthmpeentric in the extremetoMime that it ill,bur whether mming a ccnrin absmnemmputationai spccifiution a to m m n a such conscious rwermesr Thus wen ihr philarophcr lohn Searle. who is famous for his a n a d s on the equation of mindmr. with roftware. allows thet "mnuiownns might h.vc berm ~ o l v c in d q%ams thnt arc not carbon-bad, buture wmcatherrorl afchmisrrydtognhcr" (Searle. 199I p. 91). Whet k a1 iuur, if is wonh repenink is not whcrhcr othcr kinds of stuff and rubrr~nccmight suppan ~an~cious awarcnss but whether thc fact thnt a sysfem exhibits a certain mmpuratioml profile is enough (ir "suffiricnr") to m rurr th., i,ha, ,houghts felings m d
-
medium. of thc b n i n stat- involved i n r bout of black drpnsrian will not add one single iota lthmk hnvenl rn the rum of real sadnes in the world. The mend worry (mlatcd to, but not identiui to the tint) is that many feli n g m d motions l-k to haw r dear chrmirnl OT homanrl baris a d hmce (hencrl) may b. mistant to reproduction in any merely electronic medium. Sure. a silicon-baud a g n l u n play c h e and n*rk cretca, but cm it g n drunk, ga an drenalinr high, rnpticnrc thr r f f r r n of mstasy and acid. and w o n ? The (gcnuinc) intuitive a w l of ! h e mnridmrianr notwithstandink t h q by so means conrrilulc the h a k - d o w n anummts thrr' ma", at Snt a o m r For w m h i n g here depends on what ki~dofphrnomrnoncansriaurner rum$out to k.Thus suppose the skeptic argue rr follows: '-en i f you gt the mrnll inn" romputational profile just right. and the ryrtem beham just like you and I,i t will still be IkIYngthe innnhthaolchcmimls, hormones, and ncummnsmirtcrs.ar. thll flood our bnins and bodies. Maybc without t k s e dl is darheu within-it just laob likr ihc "agmf' has felingr, emorions ac. bur really i t is jvrr lwhrr H~ugclandl1981al lcrmrl a "hollowrhcU."Thispsib'dity h v i d y n p r d in lohn Searh'r nample of the p n o n who, hoping to cure a dqcnrratiw brain dircaw, ellows pans of her brain to bc pdually replaced by silicon chip. Thc =hip% prearwe the input-output functions offhr real bninmmpnents. One logiolpab ~ibililyhere. Snrle ru&csfs is thrr 'as ihr rilton is progressively implsnted into pur dwindling bnin, you find that theam ofyourconrciour cxpcriencc isshrinking, bur that t h i show no cffm on your mcrnal bchrvior" (Searlr. 1992. p. 66). I n this rcmario (which is mnrly one of wml that Scsrle con~idrrs).youractions and words continue tok gcncrared .r urul. Your loved onesareglad that theopnation i s a suanr! But from ,he inside. you epriencc 1 growing dark,,""lil. one b y , nothing it I&. Thlherc is no conwiovrncs there. You are a zombie. The ims@tary c r u ir problonatic, to u y thc Iran. I t is not e m clear that we here conhont a gcnuinc lngiul posribiliw, lFnr dsailcd diwvaian ue Chalmor (19%) and Dcnnm IIWlnI-jun look up zombies in rhc indemll Cmainly the 8Ifcmaliu~rccnaria in which you ranlintne p u r conscious menu1 life with no ill effms hom the silicon surgery strikes many cognitive &entins (myrelf included) as the mom plauaihlc outcome. But the 'shrinking consriousness" nightmared m hdp to focus our atlention on the nghr question. 'The question is, jurl whor ir LC mle ofall the hormonrs. chcmi
..~
~~~~~
CHAPTER 1
24 fla. Mmd-dreting'drug%"
/
MfAT MACHINES
far siliwn-bsd C%nkms, m y thv. t s k the form of bh&-mzrkel rofwarr p r c ~ p s c k g e t rhn mmponry indue a nor pnttoft?ow b n c g d o n 2 ~ i ~ intheold hard-rc. T h m rrmatns. n o m t n , a mend pnulhdm(; p n h a p i h r a p n c n ~ ~~ tdu r c ~ ~ f ~~~~~~~-~~~ mrnt.1 n~ ~ clife ~ s n o lor l. n nor ,iussl. afunnnonolthr Rowof~nfurn~alios~ Po. .~ .hrpr i l i r t a r o m c d ~ ~ r d i m t r f f ~sarncstill-m-bc.diivcrd r~af phyrialcruv or mn a kind of b t i c pmpey of romc ~ y ofpmatter (for mended disunion oflhcw and 0th- ~ i b i l i t i euc , Ch~lmerr.19%). I f this wrrc true, thm phing the information-processing ~rnfil. exactly tight would niU h i lo yarsnrre ihc presence of camxiour erprirncc The frog at thr banom of the beer dau i a thus nrmlrd. Thr brdrod;, uns o h d pmbim k whether conaiovl . w w m i m infanalio"dph.nom"mh Conrider the diffmre. A lunch oordo i s u m i n l y u , infarmntiand phmommon. You ran phone it. f a it, E-mail ir-whatcvm the medium, it ir the ume lunch or. drr nut .~. no one mer fmes vou mur lunch. Thew h, of course, Ulc infamous In , mnn Pin. &rvcr. You r ~ i f rim, y conristrnry, and rapping a d awail !he on-n s m d of the fan. But lames Gldck m t l y commmtd. "By lhc time r huvily r n g i n d &re engine dcliverr the final pmduct, you be@= to surpea ghat thy'vr acrunlly forgoncn rhc difference &en r p i a r and apimmaf a (Glci* 1995. p. 14). indnd, ir Scade'r zruation in a nutshell. Scarle Mi- thal the mnsciour mind, like piul, just nfn'ian informotionalphrnommon The nu#, lik the topping, xall7counts. This muld k the 0%.notice. even i f many of the 0th" central ~haracrrdstioof mindwrc r-rd an undersanding that is i n d d mow informationalthen phyicrl. Fodor's -f on mron-guidd ststrmnsitionr, for cramplr, is aprcially w U deigned to i c a st~ tention awy h m crwrienu m d onto cspcirin (such @ drciding to ztay indmr. when it i. raining) that mn k visibly guannmd once a mitsblc formal, funaiond pmme is fired We are now to +I1 with the frog. To the extent that mind b m informationdphmomenon. we mryhccanfidmthrtr gaodrnavghromputationd rimulationwill yidd m actual in~tnnceofmindfulnnr.A gmd adrimdotion of. dmlator if m instance of a dculator. I t adds, s u b m a d m dl the thine vc CF p a a a l ~ l a t o to r do. Maybei t nm follow the a m r hidden pmrrdurn ar the ~riginnlalrulalor, in which ase w have what V y h p (19861 t m r "Strong quiv.lencc"-rquivalcncce r t the level of an undalying pmgnm. I f a phmomeno" is infomtiorul, rrong q u i d c n u i s surely suffiucnt' l o gumntee lhsl we ronfronl not just r model (rimulrtionl of something, but 1 arw asmphr iin~
~~~~
~~
~
~~~
~
.
*
mi,
rantistion) of t b t rry thing Fn noninfomutiond phmomm., such usbring r piw," the d c s am diffcrmt, m d the flmh romm into iu mn. l a canwiourna like crlmlnion, or ir it more like pi=? The juy is still out 1.3 A
Diveion
[?%isis m n d fmm a soy by Tern. Bison c r u d -NimNation" fim pubh a d i n omm 119911. ~cprndurcdby m d p c m t ~ ~ i or o nthe author.) 7 h $ m mrdc om of mar.' "Met?" -Ma.! They're m d e out of mat." -Met!' Thcre'rnodoubtabouti~W e ~ & f r o m d i f l m n t p ~ u o f t h e p l u ~ f tmk them aboard our =on -1s. ~ m & dt h m aU the wav throuh. Thwk camplctrly mn,." ''That's impouiblc. What abut the radio rigndR The -ges to t k nrm' T h y uw the rrdio wm to Ulk, but thc signal don't come fmm them. The r i p d r comc hom mashinn? "SO who made the mchiaa? who we to w a n " "Thy made the nuchinc. Ihn's whrt I'm tMng to rcU you. M e t made the mxhinn.' "Thnt's t i d i d o u r H a un m a t m& r marhim? Yw'm asthg me to & lime in sentient m n r " "I'm not s r h g you,l m telling pu. ?%m onh~rr. arc thr only rrntimt r a u i"the & O r and ,hey',< made our of mu,: "May& thefre l i i the Orfalei. You how, a arbon-bad i n t r l l i p r c thn gar through n mert srrg..' "Now. T h e r e born meat and they die -1. We studied them for m n l ol their life rponr, which didn't sake wo long Do you h e my id" of the life span of mat?" "Sparc me. Oky, mayhe thefre oiclyprl meat. You b, lie the Wddild. A m e t h n d m'rh m electron p l u m brain inride: "Now. We thought of that, since t h y do have m a t hnds l i i the Wddilti. Bur Itold F, we p r o w thm. They're mrrr au thc w y through? "NObrain?" "Oh. there it a bnin dl righr it's funthe1 the brain is m d e out of mpit!" "50. . what d"" the Ih,nk,ng'"You'n not undcnund>neaw you! Thr hnin d o n thr ihin*ing Thr mnr.' "Th,"lun. ma,' Ye"',, .'kl"l mr to b r l i m in ,hi"U", mnl'
-,
rnh
ir the whde dnl! Arc you getting the piare?"
-
"Omigod. You'rs soioua thm. Thy'rc made out of mat:
CHAPTER I
16
MEAT MACHINES
.~rndy. ~n Thrr a s indeed made out of m n h ~d t h d n k e n y m g to g e ~m tourn -7th ur for dmon 2 hvndrrd of lhrw ~ l s ' "s" wh.1 dm. ,he me,. haw 8" mmd' it it wants to tdk to US. ~ h c I n imginc i t m n m~q l o r c the unim, mntsa 0,h" salients, l x l p id- a d infornutinn The uld? -wc.rr ~uppascd10 t.lk to mat?" 'Thlhrt's the i d n That's the m n ~ s g t h c f r esadingout by ndio. H d o . Anyone out thee? Anyam hamd Thnl son of Ihimg.. "They armally do talk thm. They w wrh,idea& mmrptar "Oh. ye. k e p t they do i t with mat: 'I thou@ you jun i d d mc they used radio.. "Theydo, but what do youthinkiron thcRdio?Mcst.ound~.Youhow how whm you slap or fla m a t ip t makes n miset They ulk by flapping their -I rr each other. They a n wen ling by squirting .ir through their me*." -0migod. Singing mar. This b sltogehrr loo much. So what do you .dviulm .ORidaUy or unofficially?" ~~
-..,.
"O-.L
~~
~~~~~
~
Yes,a rather shy but mt hydmgm cow dune intelligen
again:
~~
"
'Officially, m are q u i d to sontam, mlmmc. and lag in any uld dl mntimt n c c s or mdri khp i n the qvldrrnr without prcjudicc, far. e~f w . Unofficialh, Irdvi.. lhrt w c n u the rrccorh and for@ the whole thing.. 'I ws hoping you would rry that.' .n w m s harsh, but t h m is a limit Do w mny wnt to & ronnn with mat?" "Iym om hundred -1. What's t h e to uy?" 'HeUa, mat Hm'. i t ping?' But will th'b work? H m many plan* am m dealing with hem?" "Junone. T h q u n 1-1 l o a h plsnctr in rprdal m o t mnuiinm,bur they can't linan them. And being mat, they only trawl throu* C w a c s Which luniu thnn m the & d light m d m & a he w e i b i l i y of their o n r rmking cont a d pmfydim. Infinitesimal. i n ha.' "So we just pmtmd there's no one home in the univeru." "That's it? "Crucl. But you mid i t yarncU. who w n t r to mrct m a t ?And ihc on- who have k n aboard our v-L, the ones p u bmvc probed?You're sure they won't nmrmk?' 'Thcy'U be considered cnckpots i f they do. We went into Iheir herdr uld rmmrhed out their mclt $0 thst ='re jvlt d m m to them. 'A d r a m to m a t ! How r-gely ippmpriatr. Ih.1 vc rheuld be mar's dmm.' ' ~ n dwe an mark 1hk -01 uncaqied." GOO^. ~ d offi&lly , u l d unaRi
"They 11.om around.. ' h d why not? Im* h w unbembly, how unvnmbly cold thr "nivcrv would be if one were all .Ionc"
1.4 S m w M d R e d i n @ Far an u p - t d a l r Md Me4 am&, -pun*. a w n ofthe ni* m D. Qllmcm. NCunwiwiu Mind (Nor Yo& M o r d U n i r m i ~P-.
. -,.
qdwbr 1%.
chap
...A,
F o r & p h i b k l ~ u n d l ~ t i w t h m r y , b d u W m , nwhinr hnmbnh )I ~ m d p b u to mn ir ~ w dIofi this rat m d thm P. M. chwhlmd. M W . b CaawMllmas(Omhtidg+MA M m PrrU 1984. and subqlunt @diobns). holkrm.llmt m u r i c i r D Braddon-MilrhcllmdF Ixhon. PhilorophrolMindand+ nitia i M r d , England: BI.rhrrll, 1996. Chmptr 1,2.3,5,4 md 7). Fm the k w d n o ~ o no l o r o m p r ~ r i o n ~ t w o f m i n d ~ r y ~ ~ n t r a d n m b~marun g~ .bn4 M i d h i m 1st d i a m b t i d ~Mn . Mm ~rcu.1981) snd ~ , n hip d n(cambridv, M*: MIT Prcu. 1597). The f o m m ("hxnli. e n p a : An innodunloo to mind dargn.1 irnwidygaodonthe~nUw~ntindirtinrtion.andih.lincr ("mbmind design?? ddr d l dwsrian a1rwmt dmlopmmb. For mo..on Tvnng mnihinrs % I.Kim. "Mind m r. mpu:, ICh.p,",ofh.n.
+
pa SYMBOL SYSTWS
Symbol S ~ n m s
'9
v r n n IPSSI, so being a PSS ir dro r n m u condition ~ for " g m n l intelligent khsvior." h.N m U md Simon u e q u i d lo r m l * ur thur ronf.0~1 a stmng empi%ulhyporhair The notion of. PSS ir m m t to M i m i l a clurof amtdsnd pom t i r l mlcmr m d the claim is that ail cucr of gcnenl intdligrnt l a i o n d, as a M t l e r of wicnlifir ha. turn out to be p r a d ~ by d m m k n of that dam. So just what is lhst class?Thc question is unfonunrely, more difficult lhnn i t at fim appears. Clearly. we are kimg toid that inlriligrnt khavior dcpcnds on land only on) pmn.es Ihrt sre broadly
m n p
1.3
.
he quatian o f mindwith s o h (Chapt o I) found dear ~ i p r a r i o nand conme rompuntiend rubaance in s f l u v of work on p h p
-1.r)mbal ry~mr h phpied-rymbal system. sm dmned by N m l l m d Simon ( j a q pp. 85-118) is a phyriul device that contains a w@o f i n t ~ r e u b l c m
Noncthclcu, i t is i m p m n t to bC dear about whit this mmmitmmt 10 inner Mnbols rmtdly inmlro. I t is a mmmilmmt to the cri.lmu of a Eomptrtionrl rymbol-manipdating q j m r .I th, lml o l d a n i n w appmpetc to undnmnding thrdoiczma m p l i t i w ( m n i n & thinkbg) ensine.Thi~rldmisLhur Mh( compatible with the discorev that thc brain is a@barom vlmc mher kind of dc. vice. What matters ir not the compuntiond pmfile at the hardwarn 1-el, bur the one'highcr up" =t the 1~11ofwhat is mmctimer raUrd a "virmal dint: (This i s like saying: 'don't worry about the form of lhc machine c a d c l m k at the de. ments and aplrtionrpmvided byromc higholr*ellangurgc"l I t is at this higher, vinud k r l t h r the m t m must provide the ur ofsymbols m d symbol-mipularing rapwilier usochred with clsuicrl computation (copying, d i n g m d ammding gymbat string, comparingcvmntly gcncnrd .lmbol rtringf to targrt rqucnrer m d ro an). In romr c a w thew symbols will k mematicdly interpmabb i n w v that linc upvith our intuitive iderr about the clcmcnuofthc task domain. For oumplc. a program for reawning about thr behavior of liquids may use prowdurn defined a v o symbols far ilrms such u "liquid," *flow," "edge," v~~ous."mdmonlnc. C.C. H+RJ1979.19851. O r a rhna-pia@ngpropm may
-.
ux pmccdurrsapplid fa symbols for mt king, checkmate. ac., n.ph+lspnbd~pmHp~hek A p h v l c r l m ~ l o ~ r m h h h h h r y ~ d mm.for sned intdlignt mion (NmU and Simon. 1976 r. 87)
.w,omt
in la.f o d language. is that a symbol ~runcherd I h c kind j u t .I.drhA , m. ......s dl that mawm for thought and iintdlignu. Any such machine .of ~ ~ K i c i m ri=" t w (it h a r y d l slwaG be pro-mnl so u Lo rupplt int r U i p r khavior. hmcc k i n g a phvtd-symbol w a r n h lufiddnl for intrUi~ n c he d k intelli8mc unles i t is an insane of a phyriul-symbol -&dim.
.--.-
whemm a un. tmcc parwr might ure symbols for noun, vrrb, subjm, m d lo on. Thnr kinds of Plmbolr rdlm our own idas about the tsrk domain ichns, liquids, whmtcrcr).
System~whorcomp~~tionrla~ntions~~ddincdo~rthir~~ffrmili~~ bolic c l m m b may be termed m a n t i m ~ m n r p l r m r r y n r m(Uark. r 1989. p. 17).
The gmr rdvmt~grofxmantiollyf r m ~ ~ r r spicm, ni i t &odd be clcmr, xs that they mi*e il immediately obvious why the p h n i u l d m u k able to rnpcrt sp. c i f i ~x m ~ l l i crcgulmtirs. I t h obviour that getting such symbols to b h r w rp-
Symbol Slrt.ms
. . ... .
~
.
~
,
%ha& 11975) p m p m could. for ample, infn rhu romrons who a6 and enjoy$ r rratrvnnt m n l will probably haw I& s tip. It doer w, by r c fmina to a badrsroundknouledge b s x tamding the "wripf for r l e m nmir r a u v n n t viait. The script YM vm011 for mndard even* and a SFcid &iiccodr for m i o n ws. 10 thr &ran Mow, "PTnos.sfnndr for ,he
Soipc R a t a m n t
.
3>
pmpMnly will yield good reasoningabout chas lor whatewl. since many of the rearon-rc$pcctingtranritionrare thrn virihly encoded in thcsystrm. Toget the flavor ofthc PSS hypothesir in raion, ronaidccfintapmgrrm hom Lhank (1975). The goal of the program slow undcntmdin& given r short t c g i t w a m m t ro b rblc to mswcr ram* quenionr requiring r modicum of 'common unw." To this end. Wlank's program drploycd n-called w r i p whirh ~ used a symbolic event dwription langugc to encode background informaion rbuut n *,i kin& of ituationr. For eumplr, there war a vript that laid out the wid rcgumce of aflionr involved in 1 virir to a mtaurant (wc Box 2.1). Now suppouyov input ~rhonnory."J~ckgtxs into,h~hcI~unnt.ardcnr hamburger. sits d m . hrrr, hc lorn rhcr tipping the w i t m . " You can then a*: "Did tack a t thr hamburgol" m d the computer. m u m of the backaround informa#ion rvlilable in ihc script. ran rcply by gurning that he did. Or mnridcr SOAR I= Box 2.2). SOAR ir r large-sale, on-going p m j m that a i m ill a p p l ~ thc b r i c mnr of the PSS i p p m h w, rr m implement gmcnl int d i p c c by computatimd mnnr. It is, in many ways, rhc mntrmponw rucca. l o r l o the pioneering work on general problem 9olving (NmU, Shrw, m d Simon. 1959) that h c l ~ r rrt d the a m d r for !he 8 . 1 r h r n dmadn ofvork in artilirid in. ~~~~trlligence. SOAR ir r symbol-pmcuingtirchilmurc invhirh alllang-termhowledgc is r t o d using a vniiorm format known ar a praduction mcmoy. I n a pmduaion mrmory, knowiedgc is encoded in the farm ofcondilion+aionnmCfllrn ("prdunionr") whacrontrntr are ofthe form:'lf $uQ and such is the-, then do ra m d n."'When it mnfmnu a rpcifir pmblcm. SOAR nrthis gencnl memorystorc until all relevant pradurtianr have been executed. This r w l u in the tnnsfer, into r tempraq b a c r or "working memory," of all the rmff that SOAR "know' that lwlu like i t might be relevant to the pmblrm 11 hand. This body of howledge will include n mixture cfknowlcdg. of facts. knowledge about actions that can k 6km, and knowledge sbour whrt aaionsaredcrinhlc. Adcdsion procedure them rel& on. d o n to prform on the baris of rnrieved information concerning relative desirability Cprdcrcnc-"1. NotunUy, SOAR is able to rwr. dinatr a srqurncc of such opentionr so as lo achiever specified pal. SOAR un work t m u d r distant goal by creating and anmpting to rnolve subgods that rc duct the dirtaluc bcrwrcn its mmnt sate and m ovrnU solution. Such problem mlving is condu~tedwithin ra-called problem %parapopulated by rss of * a t e lr=pmmting rituationr) and operation$(aaionsthat ran bcapplid to the Satn ra rr to yield funher ~ l a f ~I )t is . p m ofSOARi job, @ v m s goal, to xlm a prab Icm rpce in which to punuc th. goal, m d lo
-
~
I
C.""...".
PTWNS:
...... go,a table
sit d~,m ORDERING ATIUNS: rCCl4°C m HOVE:
h
e 2:
,.. , ..:.
INGEST: n t
u
no
h c l : EXITING MTMNJ: ZSk h ,.TUN% gill ti
muas: go to <
W r : PTLANI:
@" c monw Ul ush g0
1M ally, then, thc pl r filll" .rmlric
~~~
".
druils @ n o in the stow.
~
~~
CHAPTER r
SYMBOLSYSTEMS
ad. ( 1 ~ 9 2m. . 301-3081, is thi use of WARm do m-lsubmHerrSO~~leuos .ne ~ m i ~ p-durr mi by ssrching in a rubmmon pmbkrn .pa- whae .rrucmrr h pmvided in ad--. Tk mIah thc n m 'primitiu, ua'for a muhiwlolwnm TmrroWW p d w , in the f o m of-tiom wch ch 6th fouming.
1
.,e,it
w~athcdiam~bmrrnthc.lpwtudth.hrnw of* & nivrtr~',.a.an.toihr nvrrnt mlumh
-,
rrurhopenton.ad a tut ptwedwe m.then tweed." SOAR ha KC these opntions a u to r - 4 at the mk Tk smch , by produdom asoched with n c h opltrtoc riut rpcify prcfmncn concerning its we. WAU Q able to e a c h
T k problem -con of the fonn fi' nch I seamheforamtor
Y............
& rpxr of W h l e aprnlor rppbtiary u,u t o diw d u e t h t d n uu of the chuding maneto k
uk uqmm th.t rimplifi
W~rgcr
..
hlum rubmrtion luLr A nore in dmink SO& a.a hdphrl r r f a minu un, ,. ..an a u n i d prog8mming s ~ th.1 m on svppon p l q w U n y hcdorul oroNt vau W;r. so lone w it is m u i d with thc rid11 ip(~Ui.rd rm of i i n i t m are thu "aGnia about *hrt bmduc;iau. woni;a I &~mc~p~~ll~sytrmmuld~~uibly&,u,muchuw.riaahr the p h m h r mn6gwatbns d %!mtqle pvnurd in dSOAR-bad rrYrnrh (cg.n a e m p l W in k b b m a 11. 1992). ?ha. rn&Um. tam ad nndo indmd r e k t thc wwv, p m n l mmmkmna of
I%
&,+id w b o i , - h ~ u o u t l i n e d ~ l i n , . n d a h t h w m m(mraa ( n kthan thl b r d d pmg.mrmw vtm)tb.l ur oilidb mamiwdintkta.
13
till situation (the pmbkrnl. An o p t o r is then applied to that rtrtc, yic!dir,g a no* nalc, m d ao on until (with l u d ) r solution ir d i x m d . All t h e dccirion. lpmblrm-rprce elmion. mtc gmmtion. opentor rclmion) am bud on the
SOAR POINTS
I
S w b l Systans
hawledg r n r i m d horn the long-tnm production memory. In rdditian. the baric SOAR archikturr uploin ti ringlc, uniform lmrning mwhonhm, h o r n u 'chunLing' in which a rvcrrssful aqurnrc of subgod genentions on b. stared away i s r single unit. IfSOAR hter mcaunlm a problem that looh similar to the n r l i n one, 81 can cnricve the unit and urn out the chunk4 cdequrncc of m r without " d i n g to rnrch a nd mbrtage for rhr nen moue. The aeud pncticc of PSS-inspired mificirl intelligcncc thu. dirplrp thm key Ctommitmcnu. The first I 3 the uw of I symbolic code u n m nr of storing d ofthc v t m ' r long-term knowledge. The rrcand is the depidon of in~lligcncc the sbilily to suc-fdly m r t h a symbolic pmblrm-rpacc. A phyriul symbol M t c m 'rxerriws its intelligence in problem-whing by mc-t h, by -no. .ring and prwcssivcly modiMng symbol srmctura until it mchrr a solution suucfurr- (Nwell and Simon. 1976, p. 96). The third i~ that intclligmrr r s i d n st, or d m to, thc Icucl of deliher*tive ~ h o v +a~i r ir, i r ~ like. u Ihr thmroical motivation far thcdrvdopmrnt ofsemmtirallytnnsp.rrnt system-ncr that dim l y mode and crploil fhr kinds ofinformarion that a human agent might conwiourly r c c a when trying to soiw r problem. Rovnblmm LC I 11992. pp. 29iL291) thus drwrihe SOAR .s rargning i h c ' t w i t i u , band" in which contentful though- ycm to flow in a urial q u m u m d in which most signifiont m n t r xmr in r lime h m c of 10 m i l l i ~ o n d s to 10 ucondr. This m i c t i o n cffmiveh n u u r n that tbc mmput=tionalstory will at the .=me time funnion at a howl+. kwl'sto,toy that rho*, rather d i m 6 5 haw knowledge and goals (bclirh m d d n i m l u n be encoded and procawd in ways thas l n d to m a n r i u l i y sen. dblcchoi~amd actions. This isafmu.c,jurthchd ofrtarythar ~ o d o r ( C h ~ ~ ter 1) ins** m must provide roar l o answer thequatian, " H m h rstiondihmr chaniuUy psihlc?" (Fodor, 1986. p. 20). So ihnc it is. Inlcliigmc. rrrids a,or cbw ta3the lml of delibmtiw thought. I t mnd~trin Lr &id of symbolidly r m d infarmation end itr usc in prof mrch. Such -p involu, thr gmrntion. cornpaition, m d Ulmformrtian ofsymbolic stmaurn until ihc smfied conditions for a solution are mu.And it xorh. Lind of. What could k wrong with that?
Y
CHAPTER 2
I
SYMBOL SYSTEMS
spmr
35
r a p can d c t h n out uan o n p i r i d M b i l i r y . A d s to inmitian 1-11 darn't lookmuch l i e a v t r m that m l l y undmtandr C h i n e 7 are pnctlully w l e v a
12 D i i o n A. THE CHINESE RMlM
Thc m a t hmous w o y about rymbol-crunching' mifidal intelligence i8 pre& cat4 upon lohn Scarlc'r (19801Thin- noom" lhought clpmmcnt. Surlt arks w to imagine r monolmsual English spnka, p l d in I hrgc roam, and ronfmnted with a pile of paprr covcrrd with rppam* unintelligible shape and quiggln The quigdcl ire, in Ira, C h i n e ideograms, but la ihc p m n in the mom, thol re just ha pa an a page jus~syntactic rheUa d-id ofapprrciable manins A nm batch of qui& them arrive *long with a wt of inrtructiona, in English, telling the prmn how to manipulac t h rpparrndy ~ m n n i n g l quig~ gia according to certlin ~ 1 ~Tsk. uprhor ofthese manipulations unbcknmst to the pcnon in the rmm, 1s the m t l o n of- intclliynr rcrponu, in Chinrrc, to gue!ionr (aim in Chinese) encoded in the inmming batch of prpn. The srenatio, though ~trsinedand ~ n l i k l ycannot , k ruled OUL We aw, in Cimptcr I,that my ~ ~ I l . ~ p 6 f i intelligent ed, bchnvior can bc p r f o r m 4 b y r wdlmmpuling dcuicr. WIU, ~ c l d . bsdone is, in .ae&,to 11) WI~CC the o p t i n g a p c m and r e n d p m m i n g unit of Immputo lor Bd - w i l e h a d m d finitc*urc mrchimr of r Turing machine) with hurnln agent m d hook of instrudionr, and (2) r e p l a the rd-world lurowledy m d o d in the computer'r general memory (or the Turing machine's tap) Mth howledge m d e d (in C h i n e ) i n ihc pile of p a p Under ruth timm%unces,i f the agent followr the rul% thm (asurnin& as we m u , that the program is
*
~
2.A
SFW
the edges of wimtific undentmding. Iris also poarible, howvcr. ,ha, s-1, i. right, but far d the wong m n r For the Chine* rwm w u initially envisioned8s. arid and sou@-up &on of ihc slory~undostrndingp m y m mentioned u d i o lrec Box 2.1, and %hank m d Abclum. 1977). As such, we mrr to imagine an inno cornputadonil rronomyin whichummtiully mnrparmr symbols wmbcingrmniphwd, in r n~ wise, =rial fashion. in w%ysrpcified by a furlhcr s a o f r)rmboiic innructions in short, a a r c to mvisicn r fairhi coonr-grainedappmrch in u l i c h the syrton'~ n o d hawledge, as e n d e d in the Chin- quiggla. might include wnl knowledge labour what happcns whm. for n.mplc, nameone visilr 1 muumnt) h a aunb, II.~~U~-WIIformat such the
sdpl: Raauntn, 5rmc I:ENTERING P T U N I : go info mt*Unnl UBUIID: find trbk Prn~Ns:go to l r b l ~ "0°K l i t dDVn ETmClalJmn M
d 11975. c
131)
( R e d that symbalsaurh u P l T A N S farm p r t o f r a m l n r n t dexription h. wage dcvirrd by Schmk. and u c ddned drrvhm in the progun. PTRANS, for e.xmpln signilin t k tnnrferof physiul loution of an objea.) Much of the in mi^ q p d ofSnrle'x srgummt. Iklicv., romu not from iu Id4nruaurc but from a renain d'iamfan with the I d a that a simuhtion pilrhd r that 6 n d of irwl could actualiv amount lo an innantiation of undernmding, as opposcd to a kind of suprfidal rlrurmnl ccho. Conridmd u r fully gmcrallagiul argumml, Scarle'suwis ilunr,indccd. HIlimtta ronvintr ur ,hat no amount of sptadie. formal organiutian n n yield r e l understanding. Bur rhe only-dmrr (byond the qunfion-bew'ng M i o n that s p t u is not ruffi
~~~
~~~~~~~
~
~
for w m m t i w c , e . ~ . Chur&lmd
m d ChurcNlnd (1990) for n nice d i a u ~ t i ~ ~ l is the mdec'r intuitive agrrrmcnt, pcrh8p baud on quite auflrial fnlures of the eamolr. Y a for dl that thc original though crpnimmt .mikes r n -. But the nmc k not ( u Snrle kli-1 the unbridgahiliry nithe p p hq m m and acmsnticr. I t rather (concerns)the need for r finer mined m i f i u t i o n of the mle. nnr ~ampuutionalend syntactic structure. For it is plawiblc to rvppac that if wm!?rogenuindyinslmtistr lnol j u t mughlyaimultr) m m d a m a i n r cam. putrr, a will need to do more tlun i w t run a p-m that mnnipulatesrrlatiwly high-level (wrnmd<eUytrmmparentl ~ p " b o l sfructurrr t ~~~~
36
CHAPTER 2
I
SYMBOL SYSTEMS
To bwjn caFuihir idea i w h o r fullclpmsion must howcvlr mil untilchap k r r ) . m may induces mntnn hewen hnaionalirm and WIUN Ioncctermrd (Clark, 19891 mi+nnimlism. The funnionalitt. you will -11 ( C h q t n I). identicks lamg i n a mcn8rl smtc with king in mn abstran fundand nas,when a funnional a;te b just nome panem of input%,output%and i n r m d rut* muition. rpkcn tokrhrrrrlrrislic ofbring in fhc mental n a in ~quetion. Bur at what l r w l of dcrcriptian should the functional story k told! Conrider a m n d famous thought exprimen!, thlr rlmr due lo Ned Bbrk (1980, pp. 276278) Block imagine that m wmrhow p thewhole populationd China m i m ~ l m e nthe t functional nrofilc of a uven mental sate bv hrvinr t h m pming uound lenterr or othrr formal *ymbolr. Bur such m inrtanri=tion of the f-rl symbal-trading rrmnure. Block fear$, surely will not actually poses the urge, mental pmpcnirs. At any rate, i t will not k r thinkinning. fcding k i n g in ita own right. Them will k no qualie. no raw inline, no paim m d plcarurrs for the caunrry u a whalc. The ntiour individuals will hew their own m n a l slate% of courr But no n o v a n e will come into bring r o u n q a f the larger functional orglniurion cmced by paning uaund slips of p w r dona From such ronnidcntion., Blodr cancludn ghat funcriond i h n t i n rrnnn gunrantee full-bided (auaik-invahincl ". mmtal idmtiw. But once =.=in. i t all dmendr on our (unrcliable) intuitions. m y shouldn't BeChineseroom. or Bloc!& Chiinc population. aaually haw ma], and qualielivcly rich, mental rtrmd Our dircomfon. I suggcrr, flows not ham rhr bcdrak idra char the right formal structure could guarantrc the p e n c e of rurh I I I t t S so much a. cram r " r a n g alrrpicion that Ihr formal nrurmre that will k implemmted will prove tm ihsllow. cm much like the restaurant wript strurmre n h n n e d earlier. Now imagine instead a much h e r p i n e d f o m r l dncription, r kind of "mtmhmcfiondism" that Fun the fine detailof the intnnd rurr-mnritions rr, for eumplc. a web of ~ o m p l a m l h ~ m a r idrrlationsbmrm rimplc pmceuing unie. Oncewe imaginrru~h s finer grained formd rmificrion. intuilion~k i n to shih. Pcrtupr once these mi~mformal p r o p d c r w in place, qwlimlivc m e n d n a t n xill alwap merge just as thcy do in mrl brains! It is somewhat harder to imagine jwr how thew mare micrar!rurtun1 feature arc to ,cpliratd by the manipulations of slip of p a v , beer cmr innocher of k r i c ' s favorites), or the popdstian of China. But i f r h w unlikely subrmta w n t h w delicately orgmkd. it don not nrik me rr crazy ro ruppor that mi m m t d rvrnts m@t mruc. Or rather, i t semr no monunlikly than the ha that they dso mrue in a wU+rgmird mush of # ~ Y and C wnpul! Wewill cnmuntn. in Chapter 4. r ramewhst d i f f c ~ n lvnd t of =ompnr=tiond model that ~ i s h -its dmtiptionr of Ihe forms1 ~sructurcof mind at just such r fix-pitted 1 ~ ~n.x 1 . .'mnn~ctionkt"(0, - n ~ nnl m r k " 1 approlchn m d c ~ m s n r i c t r e n ~ p a m(thcuw n, offormal~ymb~l~tostand dir~nlyforhmiliar conccpe. ~ b j ~ twenth a, m d praprlin) rainst finmnna of grain. Thn, polit formal dcwriptions pitched at a lml far dbtmt from &ill talk They do not rerricl their attention lo the 1-1 of Ncvcll'r "cayitive bmd" or to oprrtiam lhrt (in real
.
..
-
brains) trkr o m 1W millisemn& to occur. T h y do. however, prthe y i d ing virion ofattending to the (mioobyntu; and letting the m m t i c s take care of itwlt 0. EVEIIIDAY COPING
Hcre is a w r y diff.nnt k n d of criticism of the pmgnm of symbl-crunching A.I. Symbolic Al.. it h s brm s u ~ s t e d is , rangcninl$ vnrbic to conw to grip with fist, fluent,ere&yactivity. lt unnotdo w kauscruch anivityis not.and could not k,rupponcd by m y XI of qmbolially coded rule. facts, or propodtiow. Inatead, our ecrydry skill%which amount to r kind of a p n olgagcmcnt with ihc praniui world, are said to depend on a foundaeion of "holistic similarify r m o y i lion" and M i y , lived csp4encc. Such, in a n c c , is the ctitichm drvclopcd in a =qvence of work by the philosopher H u k n D m 1x1,cg.. Drcyfur, 1972, I W a DrCYfYs m d Or+% 1986) m d panialiyin~pircd by the idcnsofMaecinnrideggcr (1927:19611. Drryflu'cmml m n m is with Ihc rppamnrly bortomlar richncu of the un. dmtanding Ihar w brin$roour daily lim Rcall. for mmplc, the rimplc mtaurant *rip, whav rtrurturc was d i r p l a ~ dcar1i.r. The point "f such a i. lo apture r stnmlypiral course of event9 (go into a mtrunnt, order food, n t ir irnw tip1 u, ar to provide n m e background knmldge for uw i n problcmrolving khnvior. But human minds wcm ah!* la respond wnsibiy m m r p p r ~ mlly infinite wl afpotmfialnririon~on such a titunion. What rnll the w b o l i c A.I. program do ifir confronts 0 Manirn in ihc Unhm, or a Harlry-Davidwn ridden inro thcmcrunnr! Uarsiul aniFlrial iotclligmcc has only tm,rcal rnponws la this p m b l m of "depth of undentmding." One is to add more m d mnrc land more mod morel h o w i e d g in the form of npiicitiy coded information. [Dovg L m a r ' a CYC projm dcrmtibd in Lcnml and Feigenbrum (15921 isan crnmplcofthis n n f g y l The othrr is lo u x pow..fd inferenre mgin.s to pm.xm i .1 . k t from what the sptcm almdy knows Ithe SOAR project diruaed earlier displays romnhing of this r t n t w l . Bolh such santgis rcally amount to doing*morc of ihc smr.* .Ikil with different c m o h m . D r r M radical sumetion.. bv h that no , cantran.~. amount of symboliully couched knowledge or inferme cm possibly q r o d u r c the required 'thicheu" of undintanding, rinccthe l h i t h flow ~ "01 from our knowldps of facts or our inferential capadtin hut from r kind of paem-mewnition ahiiify honed hyextmrivc bodily and m l - w r l d expctimce. ~ hpmduct r of in ihr &in but r thir apericn~cit not r ss of symbolic $Iring rquirrrled~aw~y kind of " h o r i n y h m - - a knowing-howthat cannot k rcduccd toany set, howm r m m s i w . of'knowing-thrts' 1%. .&. Dqfm<. 1981, p 1981. For aample. w am a k d lo
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~~
38
CHAPTER2
I
%MBOLnSTEMS
-g~yourqu-autnrly.-Thenpert.
by c o n m r t , c r p ~ r e " ~ c o m p d l i n wnw g of the isuc and the b a t mo*cm Fxccllen~chrs we ace told, un d i s h y i r h r a glance 'roughly %.OW of position," m d an,i f necurrry, chmove st a speed that cNeaivcly pmlud- mnwiau. analysis of thc situation. The mulunt flrxibilityofnprn rnmp.trncc Fontma strongly with thc oh-marked "hrittlmes" of clasiul AS. programs thrt rely an rymholi~llyadd Lnowledg m d makewildccronwhcn faccdwilh new or u n c ~ r c situationr. d Erperl lulouhow, Dm+% and Dvyfus (1986, p. 281 rugsex, may k more fruitfully modeled using ihc sltmaciw, papaltcm-rccopifion.bmd tehnolodn (rrr Chapter 41 of connmionitm and aniSdal neural networks Since such c-nir pervades the bulk of our daily lim (mam ail, or m a t of us. "e-" rt making m m d raffee. *miding unliksc~idcer,-aging in sadal intendion* cookingdinner,dingsmdukhn, riding biqc1.s and $o on), the niticirm !hat such lnivirylinout. ride the sap. of symbolic A.1. is damning i n d d . I s Dm+ nghl? It is hard to hvlt the abwrratian that qmbolie A.1. m r to yield limited m d hrinlr svtcms *haw common wnu understanding lnrer plenty to hc dnind. I n &ly this vein. for cxamplc, r skeptical computer $rimtist, mmmmting on the SOAR proim,an- oflcrrd the following "friendly challenge":
I t is only fair to note, ho-, that much the ume chdlengc a u l d br r a i d regarding thr connectionist march p w i m p m t d in Chaptcr 4. My mn view, then, is thrt the "ugummr from fluent r v c d a y copingX a d l y p i n m to much that ir wrongwith hnthmnnec!ioniic and~bol-prornsingrnifitialintrlligcncr. This p i n t is not lost on Dreyfur m d Dr* (19901 who note that hum a y k cvm morc'holirtii than n r v n l nets. and wonder vhclhcr wc man king. need to consider ri 1 . r ~ "unit of mdysb" comprising brain. body, and rulNrrl cnvimnmcnt [a 'whole orwism p m d inro a whole cdtunl world" (p. 33111. Such ~SULSwill reum to haunt ur in thc cloring chapten. For now, we may timplyconclude t b t wmldaY coping p o r n c n r m r l y difficult for any staunchly symbdic approach and that m). mow a w y fmm celiancc on ciplidt, rnam-gnined symbol structures and toward hrt, flcrihlc panern-mopitionbarrd model. ir pmbhly a l,LP in the ti@ dirrnion. C RPIL BRAINS AND M E M G OF TRlCXS
mm'r deieion to fom purely on the "copitirr bmd," is open to swiout doubt. The situation ir nicely summed-up by the copitivc d~icntittDonald Norman:
ofthe ncuni b.nd.kthout romidcralion 01th. phpiul M y In which the organism is emkddd, md xiLout mluidrral>onof n ~ n - r m i f i r srmu r of khmor. (Norm m . IWI. p. 3131
Thr mrrieiconcerning thcpotmtial rolnofthephysiul body land thewider cnvimnmmt) will m p y ur in 1.8.r chapters. An immediate qurnion, h-cr. conccrnr the ancmpt to madel pqcholodcal fundons without reference to the details of n a r d imolemmation~ UO ih~pal8,c sdr. w < a n y th~r81 ir prnhahlvrnor that stlrav mmr pl chologncal sat- wll hr mulnply m r l t ~ b l rThar IT lo my. ~ r . 1dnffms hard "rrr and r a w r e orwnlulton$ w l l h ca~ahlco l ,u~ounln% " the u m r mental asn. The p i n t about multiple hardwrr rc=lirabOiry flow. dirmly fmm the M r o r k idea of mind . Ia formal np,cm, m d the canqucnt for", on at",<,urc nor rmN. The point .bout multiple rofmn rcaliubiliry ir trickier (and is further purrucd in thc ncn chrptnl. But there nisr, for eumplc, r nricty of diNcrcnt p m u d u m for a d n g a ut ofnumbcrs or lencn inro r q u m c c Muick.$on m d BUBBLE-aon to namc bul em).Is it not rimilrrly unlikely that t h m ir jun one algornhmic structure capable of wpponing. c.g. the mrntal at=* of klieiving it is mining? On the ncg.tin ride, horn.. i t is qually unWtcly that w. will dirmwr r goal model of rhc formal arructum of human thought if nr pr-d in a "rumphyriologid nruum. Conridn, for rrunplc, the SOAR ream's commimrnt fa r ringlr wr of long-tcm mcmory (but see Box 2.2 f o r m imnonant owat). SOAR thus uwd relies on r uniform pmdunion mcmory to stom all iu long-tmn L n d cdgr. 1s !his irsumpfion icgilimate! Donald Norman (among othm) a q u a chat i t is not, rincr human memory wems to involve multiple prychologiully and nmraphysiologiully dintinct rystrmr.' Far example. the dinindion k c n semantic memory (memory for fact$, SUB ar "dogs have lour legs") and cpirodic mcmory (memow c m n r n c e s and events such u l c dau rhr doe burid the . of rmci6c . tonoiw). SOAR can, i t ir true, y m d u e much of the rvrfacc behavior assaiatrd with each mcmory we ( ~Newell, t 19% C h a ~ t 61. n But this surface mimirw. as Norman pant' uuf. d m tmtllr lu cvvnrcr !he p m r i n bod, ~ of ncumpvchb lvyral crdm:r in favor of ihc prwhalogxd realism of mdlfopr mcmov mtrms. Much o l inc rrlcv=nt nidcnrr comes not lrom normal, dl,:) klmrviur hut Com
One olthc v ~ d 8 n arrvrnptronr e of rluswl vnboi.crunchxn~A i 81. nu w . that ~hcsnrntnficrmdy of mindsnd rswulion msy prwcrd wthous rrvnlrrl rckrrn
..
studies of b n i n damow and bnia abnormalities(or nrmplc, nudin of amnaiacr w h m episodic m;rnory is much mom w n c l y impaired than their urnant% monory? Thcrc is alm mmc nrumimaging wok (wing wmning techniques to plot blmd flow in the bnin) that su%gau thrr diffmnt neural a m r am s a i w in different Ends of mrmoy &k h studin all combine to %u~%mt mlsnd pyr h o l ~ c a l l signifirsnt y diffnrnvl b e w e n vrriour memory rptem. ~ hm c i n t about multiole mrmar, wmr may be a n i c d a s t 0 funher by
id,whlk hmring .hmto p b n your fm?H a m y praarr h+ hws,th. words #ha8 uy what you mcln while 8rnMns !bow wrdr into suitable s ~ i n y . rhsabovt lhowolhcr thovghlr Ulatdsrlygo on in panlidaso r r p n o f p v r k w hmrnms a mn. while mooher sub-mmd p l * I~ path ,hat nup fmrn MU p-n and appnurbn that one. (MimQ, I%, p. 1011
..
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tribukd with diffncnt brain Wona aupwning diffoent kinds of "partial rcprr. unlrlionr." Cognitive effect%Arbib %u&nn,rriw ham the m m p l a intcmtianr and mrhnned in their pnicular configuntion O~SOAR.instead of a uniform Ic~rningpmedum,singlclang-term memory, and a rmallut of infcmcecnginn, the rvoiutionary psrhologhu depict the mind u r End of grrb-bag ofquia spccidiird imovidgc-md.action nore, developedin r piecemealfashion ( m r eve lueonav time) to sew specific, r&ptivc~y impntant endr. mlhy thus iken the mind lo r S u i s army h i f railertion of ~~~priring!y various spCFiali2ed impirmrnb housed in a single &eU. Such cognitive impicmcnu (mmnimn ulld "moduls") might indude one for thinking about spatial rcialianr, one far t m i u,one for mcid undcrrtmding, and ro on (wc, c.g., the list in Taoby and Car. midu, 1592, p. 113). Evolutionary prychology p w n t r s radial m d u yet no1 fully warled-out vision. lFor a balmrrd usnsmcnt rcc Mitchell (1999).l But the g~" im ~ .gd of human cognilion rsto Jome drgrr. s "bag dtriM rathe7 than "=at, inagmted rpum is n'nning auppon hom r vnticry ofquarrca. Ir ir p i n ing gmund in work in ml-world robotiu, since rwcid-purporc trick arc often the only way to gcncratc rdsptiuc behavior in mi time im Chapter 6). hnd i t is gaming ground in mrnc neur0rcicnti6c and neurop~y~hologicd r a m h pmg r m r ? I n r grut mrny qurnen, the idn that intelligent wriviry is mediated by the ~eq~entinl, wrial rcrticvPl of rfruclvrrr fmm romc funcdonrlly h o r n gcnmua inner nom k k i n g r h d o n e d in favor of a mow ncuroio~crllyrealistic vision of muhiplr rcpracntatiod types and pmcests, o p m i n g in psdlel and communicating in a wide nng of different rayr. Notice. then, the crlrcmr distance that scparnn this image rnpitian fmm the idea (N-11. 1990. p. M) d .%in@ " L q ~ n c e ~ ~ i t dmving i ~ on~I~ i r howledge d sax. scrirl rcttiwal of iternr ham r homogenrour knowledge rrom m y work weU rr r model of. fmirolatrd fmgmmtsofhuman brhrvior Isueh i r doings rm-rd). But. to quoa in ~ i n s k r
I
2.3 Smggnted Redine
1 .
~~.~~~df.i~i~.d~i~k.!.p~lfywhLmmingrht.nd~qwthhidi. HW memy f. p m a u i n u ~ .involvd in shaping you b n d to k r thr NP %+re.
,*,S.s.
a Zah.MW
(I'UJ and T u l " l ( l W 9 J .
I ~ n u h . n d ~ ~~ . ~~ d l l s U ) . I n ~ L o ~ l l W I 1 . T h i ~ ~ i l d l c
rvud.8 lkwh m CIsdtlW71.
of a multitude of such conmrrcnliy anivc partial rcpmnntiona. The point, he mys, is that -no single. centml, logicll .cpr-ation of thc w r l d nrrd link p r ception and reion--lbr rcp-nlalion offhc world is r h e p n r m of re&tionrhrpr brrmrn dl i l r p n i a l ~ p m m a t i m t f(Arbib. 1594, p. 29, original rmphasis). Wcshould not. ofmurw, mistalv~cryctilicismofipartirular useof SOAR" bra ~riricirmofclasskal.Mnbolk~unchingh.1. prr sr. Pcrhspr one day there will bsymbol-prmcuing systems (prhaps ~n r rrrsion 0fSOARRor 2.2) 411 hkc much mom account of lhc psmUcl, dirmibld, fragmcnary namn of r u i ncvnl prmuing. Ccminly there is nothing in thc b d m k ides afrlruiul11.I. (wc Chapter Ilthat rule out either ihc uw o f panlld pracaing or of mul@iplr. rpcisl-purposrtrkbandmat~gis.Thrmarrrvrnup-md-runningprognms that prow the pint. Whal reems most at s a k e is the once-.sndard image of ihc a
h rlnarnl I I a d ,he 9-1 s ~ b iprm l h p p n l n u n A NonU and H. S m a . Cornpu8er v o m a u m p l n u l owulq- hmhvlr anduarch'ln 1 il.u~dam( (4.1. ~ , d hip 11 Lamhndw. MA MIT Plru. I*? pp RI-1101 INIU 0n~n.1 aawnl 01 .hr Phv,>.al Spsul Sm:rm i t r m l h n 3 horn hn,o!~h.mrh .unof 'bu .rl.l!lf.lal ti.
P
CHAPrER
2
/
SYMBOL SYSTEMS
gem. I f o r t h r h o d A I ndrnamm&mdmrmP Ranhlmn.1 Ia#rd.& N d l . and R \l&ad. 'A p t i m m q analps of ik SOAR . ~ b ~ u n uu~ chu for gcwd kntdmrrn- in D K l n b Id r. F u ? * r m , 01 Arnfimi inVUfpu IGmSndg. MA MIT RN. 192. W . 28%3251. For -ir *tiquo afrhiml Al., u.I. Srulc.-Wndr bmimrad progunr'ln J.Haugcinrd (&.I. MendIIIC.mbridgc.bU2 MITPrcs!. ,597. W. Ilc3-lol). (Crb, ~ t i 6 ~ r i tu,i
P-,
"e wr
PAlTERNS, CONTENTS, AND C
t ~ ~ . ( ~ " ~ ~ ~ ~ ~ ~ i ~ ~ & ; ~ t i ~ n ~ ~ n d ~ n u l n s i p i n g I~ o m m r n ~ ~ ~ ~ t h e m n -
nn.ti;, a m n i w to duud *.I.) D. hnnrt,, -*ti"* w M : Thr mnu. pmb11 olA1." In M. Boden (d.1. Thr P h i l & y o i A ~ h & l I n i ~ i l ~ a m a ( W o r d , Endand: Oxford uniwsir, P ~ S ,1990, I U - I ~ O I . ' ~ ~ ~on~ ih; ~ Ipmb~em W , ' ~ oifoGdlzing crommon-wnw r n n n i n n ~ i n m n t h MnmZ m a m a y wlvr md dlrh.1 Fa, m r r n ' ~ 0 dncn<.l*.,.. " in .mrtion'.ndpllf.l& wc5. P""Uih Am'jWAMmdl (Ombndy. MA MI1P m r . 1995. C h ~ p m 4 and 51, mndlhv6our pr&er mprrsmnted in the IIr m n r m t i m & in k t i a n II'SW~IV m&l~aimid') otw.c;~ncq.E. Smoliu. mdM.Sx& I&). Onmmpbtin~MidslCamb~dg~.M; MIT P r 4 I W I , pp. I-I*,. A "+I ~ll<.-,i." il I.H."~CI."& Mind Dnip 11 (Ombridg. M k Mm P r n s 19971, espollh (inaddiflonlo h e piers W h l r md W N w U and Simon rP.d r-, the inuduruon "Wh.1 &mind b r i y ? ' b y l . Hl~gcluldrnd the pa)m by Minsky('~& m r k far mp.ewntinghorrldge"1 and DrNfvr ("From mVm-world! I . tmwlrdgc rcprewntai~n:*.I. at an impad).
PP.
, ,
,~~~~ ::, 'I~,.,.. *.w*3r.&' .,':
3.1 Sketches
~~
:,+.:,; ., . .... ., ,. .c, ,l.$,,*.
me wduni~ni~ I Y I C of V ~ O I - C W I C ~ ~ ~ ~~
Iivedencc, for the phiioropher, lay not junin ib pmmiw toexplain i n t c l i i p t behavior. 11layalm in the pmmi* of rmounling, in a nth" d i m I... 1(1 . . ,;:* < . my, for the dnmrtic explanaoy m d p r d i n i n , , . .,. . ".. . pawn of daily mmtaliaic diwounc. Wr h r n reen hinlr of this intcrat i" the ~mccdina - chap . tcrr. I t a now llmc to conironr *e iuuer h a d on. Rccall Fodar'r rugglrfion ( r e h e a d i n the Intmdudbnl th.1 the prmie of w i n g onc another as mental .gat-3 loci ofbell* dcaim and soon--mver ur w, well bccnuw i t emhadin r h i d y uuc theory of our inner -kin@. It vorlu bcourr &lick d e r i r s and the likc arc i n d d ml i n n o with o d powerr. Fodor'r bdicf, rlnrly Lid out in Chapto I o f his plyrhomantia (1987). is that the bcdrork m r y f o l d by symbol-crunchingmificid i n r c U i p e L largely rmc,md *rrth~~on~tisar~whntiSc'vindi~~tion" (Fodaf~fmlofduly'falk payrhologiul.. diwourrc. Fodor thus holds that the image of mindware u a colledion of inncr symbols and comput.liond pmcase d&ncd over them a a d y shorn hovtnk of bclirfr, desire, m d n,on u n bc (perally 8perking) m e , wcand p d i d w l y pofmf. Thcvindicstian, pmprdyhidout. 1.l;rathr fomafwhat Fdor d k h e F q . -ntrtiond Theev of Mind (RTM) and it a e r like uhir ,i;.
;$$* . .d? .
1
1 I
I
I
i,/ ,
a.
I.Praporltimd anihldcr pidr out m m p u u l a d d a l i o n r to 1nt.d
qmena.
tiOD$.
2. M a d p m ~ a r aare o v d p-u rrp-nutionr.
that imht ~ d r i o rb.tmn i~ in-
i
-
CHAPTER 3
U
/
PATTERNS.CONTLNIS. AND CAUSES
T h e nro d i m s (Fodar. 1987. pp. Ib2O) yield a wik. simple . a n t of the aurpning r u m s of folk p ~ h o l o g ym d of the phenomenon of mrwnm p m i n g chsilu ofthought. For the folk pryrholopid discourv is now imagined 10 UIC* real. cdiu~Uypotent innm rfatcr whore c o n t c n ~ at 1in central usrr, match the mntrntr specified by the "thrt.clause." I f Iprrdict your goiog indoors beuuw Ihave bccn told you &limit i n going to rain, my prrdiition w o r k [OFcording to thii story) bEUw y o u bnin d a s indnd contain m inncr sntc h a t ma", "it .going to mi"" m d b c o v v lhrl inn* .r.tr i, such u l" uuw both b n h r r mmrd stars (such rr your hrlicf that it would he wire to @ indoon) ud raianr (your aaudly p i n g indwn). I n Fodor'r words: 6nt apprmimnion. m ,K"k.ih pin8 to mi.; ro I'U go i n b . is lo hen I to*ming of=me"t.1 rrpmolt.,ion ibt mean, l'np i"drn""unl, in. .m.in -7, by a tohing of a mrnld mpremlsion that mans, ;ti pin# m mi". (Fodn. 1987. P. 17)
To.
W e have slmdy m u this kind of nary in the pmirms chaptm. The anru thlrc ms on showing howra%oditymuld be phyridly ("mrchani~ric~lly') pmsiblc. I t is n m clar ,ha giving a simple. wienlific s o y to explain the r u m s of folk pmhologinl nplanation and p d i a i o n is simply the 0th- side of the smc coin. The key move, in both i s to uun that mental contenu and inner c.udy potent * . , a much clawly in srrp. camonrcnre ps~halagywork%.c. cordin* to Fodor. k u u it m i i v d o n track thee ceurnllv, wtcnt inner rmt= There am, nrturdy, rame caveats m d winWes 1% c.8. Fodor. 1987. pp. 20-26: U a h 1993. pp. 12, 13). But auch L thc big picture nonnhcirw. But wtut if there rm no inner r n t a dm $0 dorcly match thc l t r v r N l a end contats of prapasitiond attitudr talk? S U B ir the nor of z wrond proupnirt in the d & ~ over folk p f y ~ h o l othe ~ . n~rophiio~)pher Paul Chucchland. We shall examine, in the next chap!". the rhrpc of the d m r t i w ("conncrrianin7 visian of fhc inncr m l m that Churchland mndorwr. For the pmwnt. it 411 suffice to trk. note o f hi. wry different rtrirvdc t0w.d commonunu psyholw. Commonrenw psyhotogy (see Bo. 3.1). Churchlend&liner, s ! a gunrkil~imtific thmryof the Y-n (nuus of our behavior. But whFodor think, the t h m v ir b=sially mme. Chuahlrnd h o l b it lo be superfi&l, dintonivc, and hlu both in spirit and in dnail. lu predictiresuccess. Churchlad tiqua, arc rhdl o m s n d i r r r ~ncompvringthsnPodor and oUlm h.licvc. For -p+ Churchland (1981) depicts fok pryrhology as insdquatc in the,
.
I.it w o r k only in a limited domain l v i mmc ~ upctr of thr mmtd life o f normal, human rgcnu), 2. its origins and wolulian gin rrvv forcon-, and 3. it d a s not wnn to "fit in" 4 t h the mst ofour wirntifi. pictum orovrw1rrr
45
~ d (m b d mcnt.1 s ~ t mJU&
klic*inc
h'op.c
rfyn i%
uciwith
prowtiom (eg 'it b nioig')to d e b & the inn" dkpring of h m d o n . n u Imight n p h p inul ofrunby eying that p u &I - Uut alu rap un & h a d m d desk 8 long md healthy l i or pur ping to the fridge hy your c ,&your &liiUutlhmhb+"inlhehid~.
,
.
m p p hxr?me id- L that it iranly b e u w wc i m p l i q y d i t i o n r such u &Id
k hp.
b t w m t s d dd for- as q plidt lsw n gur & o h should, i. lion, ror C l l h 19.87)
~ h h . p r ? hwsheiungnlh u 'I sate or brb.1mr. If a body o nimts a theor)r. then common .....,rid tbr0mk.l ,. ..
Regatding 11) C h u ~ h l m d dtn r l q , nntivity, mamoi-f, m a u l illneu, md inhn!and animal thought uphcnommr onwhich Mkpryrhologlhurhed noiight. Rcprdimg (2) hc notes the gmcnl unrrlirbilityof unscientificfokthrorics (of u. and progrcurd o r o ihc m n R%.rdnng I3 he nolo lhrl then n no ilgn i r m ulmy qslennatoc fransld~onol fhc lolh u l k tnto hard nrvrow#rncc or yhy0c, 11 I? l h n last worn that.. lthmk, m u U v bnn moat of t k mpht of Chunhland'r kpticirm. HI belicvcr like Fodor, that folk prychology require a very r p d k kind of 'lcirntifir vindicslion"--onc that . f f ~ i v r l." rmuims the d m ri ," of in. ncr i1.w that Bare thc contam m d srrvrmrcr o f @he folk p s y ~ h o l a ~¶rrl ,us Bur whereas Fodor, innucn.rd by the f o m , of b i c ph,5i
.
CHAPTER3
46
w Churchland bdiw-
1
PATTERNS. CONTENTS. AND CAUSES
is d i i d i t c d . His rondlllion i s thm dimclly ~ ~ ~ o to a c d
Fndor'r.
.
nsdan m l i d y n r r kinemrtia a n d d p m b vilhrhich tommpmhnd hufmm ranpurntiand nrumwirnrr and mnneaian*tAl. Folklayekoloplesuldthrnbcpuf aside inf-r dthisJrwripciwly -re rrmmte md .rpl.n*to"$ more parrrfvl pan?q9l of t h mlin within. IChurrhland, leB9.p. l l 5 ) We..
m mgnitin airirr,Om drawn, ph.p.
a third parribiliry: pcrhspsthc (putniv.1 k k o f inner m r ir not w, damning ORE. aU. P c d a p h fob trrmnvoa does not nnd"vindication'by m y such inner wientific story. Such, in barst oudinr, h @he view of the third key player in this dehfc, the philoraphcr Daniel Dcnnm. Hc a r k us, for example, to consider the foliawing nol Thneir ho-,
I
d analogues to lhc folk appantu.
S u p w , for the LI*L of dram% that if Rums out ih.8 the mb-pnlon.1 rwik wchalagy i t h innnmgnilivcoryniutionl e l m peopkhlmsouttohdram*ially diffmenl horn ih.! ofathm. Onr a n i m r g h c the nnmppr headline: "Stientism Pmw Mon kh-Hsndm Inupohlrof 8 d i d " o r " S m h g D i w a w v - D i h i u H a n No mim.' But thxr is not h a n m u l d uv, no m a t t s how the wienu tvmr nut. And our rrlunanrr -"id no, hj",,<~""~'"d ~onrrrndrn,b , rhr remgnitionof 2" &"lour .mpirir.l far,. For 1- id urd "&h-h.ndm lor mcn md womm, or .ny olhn subsor of peqld bc u inlrmdly diliwml u p u lk.wx ~ I r o d know y that Ihcrrarcrdiabie,rohunpnnn. in w h k h ~ l l h b v i n d ~ n a r m a l p t o p l ~ p ~ n ~ t i p t c #heptbms wr indilion.llydrwribc I" terms afbelirfanddnim md ihc ulhrr ierms of fok-wholog/. IDmnm, 1987. pp. 23CZ35) I t will k uxful, at Ki paint, toclrarlydininpish boro w o f q u r . tion that may k m i d mncrming the appamnt ~~~~~~w. of mmmonwnw pwthology, vir. I.Empirial or xienlific quertionr such at why doer mmmanwnw mcnt.1 h l k work in the caw 06 c.8.. normd. adult human agents!
l u d a w b l murf b d r caw i f such rommon$mv nplanalaun, arc to hr gmd, pruyr. l ~ ror. o l h m v I*.
2. More ph~lamphralor conrrptwl qdellrnnr
pllmslc, for humans or lor mrolho k m p %we mav onr davmmunlrr'
Thor n o bmad
.
..
.
3. What determines mcmbcnhip of the general rlra of being that may properly bc dacribcd m h g the appmtur of daily mmnlmic dirmurw?
Thus for example. the s m a l daw of $me'
inrluda omm m d hydmgcn, and m ~ m k n h i p i a d r t m i n by d lhepmprtydinddinilcapsnpion r t o r d i n a v t m pcrrmru. No1till general darul, of
."
=oro b j a . . .rhaw bm-r
i s allp d h d by !hi rmtw is in ihr fvllrn 01th mrd. b d i m . W b l i t " I. b.. true hlin.r"to b. intcnlirml ,p,m.
0
vtrmrho.rbrhrviori.rrli~bly~ndwluminouslyprdrt~bIm.th~intmtian~lm~~w IDennm, 1987, p. 14
PA* &f Denncn's projm hem is to ronvincc m that rhc rarnmraneaf t k d's. linnive kind of k h r v i o n l mccus cnj@ by human rgmrs is pnciuly the kind a f d d r d g n displrycd b y s v c ~ w i d c v a r i c r y o f r r u r a f b i o l o ~ c a l ~ t ~ ( p l a n t ~ other mimalrl and by some humanly c r n t d anifam. me leading idea is that commanwnw pry
..
4
CHAPTER 3
Pamrnr. Conhnts. and causes
I PATTERNS. CONTENTS. A N D CAUSES
49
!
h i d o of content m thought m d mn -. iMer i t m bur Lhc
it rep-ta %hie wd arcavnu of con.
awh thaughu gn rh& irmntena in the S n t ~ h hother . w q to nk thc quation L this. Consider our aid himd thcpodrcl aldator. I f hla a P ~ F iol srmcturc that ir wr might my. foirmra a <main i n t q m t i v c practice wherebywenut it as marupdrtigrrpr-udonr of numkrr. But it might llro toierrte wmc other intcrpmstio-mybe sr nlculrting good m a w in some alim b a d gunc. Suppow now that & crlculeror w s naturd phcnommon, found growing on Mua. ih r p p d to ru< live pnrrire muld not dride which, if
ri
comlnion. Mornmt. thm L rubmnthldcbrr w n r e d n g t h e p m p r w mcr bmnrn a p W m n u m w and to b d contmr, eqmidy in ifw conrm of plchala&d end f&-pvcholeghl aphnstion. n u s lorn.ainhon klimthat appeals ro b r h u c nrmuvu, lr to capbolh is emIluand what h diff-t in the aw of bnh-hog. and Nirn-hog, nc For mareonlhac topiawe Kim ll9%.CbapterB), Btsddon-Mir&dl .ndIwkron 119% Chapml 11 a d 121, a d (for an drcmatiw vilion) Cummim
a b u t ronmt. 3
-"a
-0"
(1987J.For a much m o r c m m p l n o d nory, c e F&r
I.Cootmt "itvlfhrrd p m p r t i a of Lhc bo*
2. Carlent wie dqndins m br& ~ rI h +rlrt .nd the nk,rions b e m n itr inn" nrte a d a
-....
Ifmotmtisl~dclminodthcaUunmh smh that it a n k h r d 61 wo phyiuuy idcnrid h d r r cantot i n which thy oprrra is very diffc~nrh long u the k d -dons am the arm. 10 will k in : othcrr t m n 'olrmx wntmtr:
who xek whal ib good for them. and who perceive thing lhlu m d o w d d i b i t , in Quinc's tender word* A p.lhnr but mi-nhr
1%'). p. 126)
-
Crraturcr not
* n d e v to dlr brrorr rrpmdlring thri, ~% ,,n i ,~ ,(d
The intmtiond stran is thus pmcnlcd a specid o w orwhat Dennett ullr the " d n i y nsnrcmviz. a m y ofundcrnandhg objms by mfcmrc to what thcv
P
CHAPTfR 1
PATTERNS. CONTENTS. AND CAUSES
are *vwrld to do. What the intational
of ita nnda. T h c d m l i i b m r n n the intcntiondnuvcmd thcruumpiaar of@ d c sign and rational choice mean6 of course, that there will be x u r i o n r when thc nrs~qyhas. For d-iw m d croldion arc. at thc end of thr dsy, urvbk to pruduccthc p c r f m q k r . T h c p a f m cogliurxauld be, for ~umple,rwre of aU trvfhr pmnc to no illurionr or emn.m d apablc of inrunt c a t . f w drcirion ,".kn i g. Would that wcwcr.! R d cognilcn, bycon,ra*, arc i b r s t i m p r i K t englnu of -n m d prceplion. R m l I m.Den may, far nunplr, rmplay m opt i u l m m mbilct to the following illuriona whm the light rouw is dim a d a l m mglc of 3 7 to the ye, ydlow look g m andvice-. Bad nrm for m n i n g mcalr! Bad nors toa for ncnin&.ppliutions of thc inb",i~".l stance, for undcr tho* specific Ncumuncrr a prediaion b a d on the i d n ihu the ryrtem will ad oorimdv, will fail. mwill ear the wiron omides m d suffer thc conscoucncrr. T h e in,cntianal srrncc r. thu. a tool that wc may u u t o makr u n w of the bulk of the drily behavior of well-dsigrd. rational bdng* I t is a cool that will, haw-, fail us in the face o l d n i p flaws, hardmrc failurn and the lie. Gmmonor^ m~ntalisti~ d i ~ u ) ~ h. othrough l with f h YX ~ of the intcntiond nmcc, is thus to br viewed a.
.
.
Wha I% ma! mntmltous about Dmnm's dalm is the id" lhal bcmg 1 klhmr l w h r h *c now $realas shorthand for h n g ihr propr ob,d of. ,may of ammuc,odanomdr .unnronsl owl rr b r m " r rmturcwhnsr khanor can u u fully be undmtood by mans of thc inmtiond nm
puw it.
..
I t ir wnh bearing in mind, he-, thst Dennett q l i c i t l y rejrru thr i d u that 'kingti bclievm" is a11 "in the ye of thc beholder' Instead, the daim is thrt the intentional stan
hild to rrr the p r t r r n would hc missing 'mmnhing perfectly objmive" (Dm-
;
.
ntioduliak (i.r.mnuliv-urmingl a!alul ofinrrpnlmhn md prrdidioan iddid"& *me, inr,",mnd*i i"tnprn.ti0" mnhod .hat ha r a h l ka u u it wrh and that mr*r bra- rr haw mid. (Dcnnm, 1987, p. 191
. ~ ~ . ~.
he ammnc h u of klicrina thau wrr h-r at o b dc hand, h e fmurr t c r m i d by the (arribkl pdirtiw$lnt.gr o i c l h m IRuddm-Bk, 1994, p. 3341
m a adds to m ordinar, d d g r -
nm, 1987, p. 251. r h c u p n r m a ~ r dnccrn~blc, r hownrr, only through the .pcid lens of mcnmlinic p s p c t i u c much as an obimive pattern i n 1 light display may bc diwmible only via r lens thrt highlighll s p ~ i f i chequcncia and rvppohm 1s- Box 3.31. Thlr rmphs3ir on "4p t t a n a h impnnnt. For *st Iknnt" mart cars is the "mirpla
.~
,
.
hiim.. ..-
f i k thaclthv .-I .b~ t h r than , ~ f t -furniuunl h ~ ~fqh~ phpidvorld'md C-I ~ l u i h u v d i n i c l u m m s h n ~ r r i n n a n l y i i r o n n p t ~ m fmm 3 < w i n lunilhr Ymdard ofliunliq. [Dennnr. 1987, p 721
V
!
l h c p m d r lrmaurc m d amrulaoon of the folk fnmnark, k n r n bclion is vnlikcb to br rcpllotrd in sny innrr amm. lhr gmuim innrr ronortr -1 m look ~ n w h ~ nl~ke g he klids w to bc found DD the h ~ nbe, tdenlih in #hefolk diwaurx. Instnd.. !hn, rillb. 'uvo unnamed and unrms=. idn r d bra-rtmclurcr of w t l y diRersnr pmpmie" (Dcnnnt. 1987. p. 70). B a t h e folk Irk nonshcles e w e to pick out ml pnncmr in the behavior of more-or-lcrr ntional, wclldcrigncd rgcnts. Such folk o;plmatians arc (for DmMt)no more undermined by, the !<. I of romspnding inncr cont h rr. rcientific storis inwwns. encnsionln$ items such ar renterr ofmviw. The triangle ir thus mmplea. At the bax, m d in d i r m butpurely cmpiriul oppuoloon, vr 6nd hduc 2nd Churchbd. Fodor r-r w.m
similarly, the qurnccr 2.4.6 and 8. 10. 12 am diffmnt yet uhibit a common pattern (add 2). O b i b e plnrmr "mout' wbm we view h, n-' m i d rhrouh appropriate (inlh'i Lucr t n t w =tnnct. a n n e t is saggnrinp. is
...-.
E. D - ~(19%)offcn the c-pl ia In the Life-voM m m p u w aimvlrtiorr ..u,..,u,, u.uv.p... Jir~laycda d in accordioc~n t h thm simple dn dcfvld o w the (maxim a ) eight neighbar. a1 41) an the grid: Ruk 1: I~+Iwo&[
kc
:,I& .qum re"
or ins*^).
Rule 1: I1 Rule 3:
E
ngnmnucwoinah
LCDIII" a",-.
\i
'1
dmh) of active aUs a grid ~ 3 r with d sow hitid&ty d i i p l m a hsG a t i n g h n d of behrvior. Mine lk form s h p u that penin, intc- dr cay, md pmpry.$e.n n c t w l t i n g - d 4 un k d a o i h d wing a nr obulq p r d to the -grog m m c a t a m d p m .A 'flrrhcr; for a m p l e , o a r . whm p n of the pid id irmnflgvsd in F i e * 3.1. Apphingthe a m p nrlrsWI(nthe ncn tim atrp) F i r r 32. ~~8 tbc nrln rrtunrr urm tbc 6nr [email protected] ra it willwntinuc ('fluhing-1 unlcsr i t h intnrvpicd by d v i v pmpag3tiq horn d h r r on thr 6
-
Chvrchlmd anticipates no such match and pronounies the fok fr.mwork mis~ ~ i and d ~ chimerical: d r "dead parrot" lchvnhlrnd, 1989. p. 127). At the r p n . md the debate in rather d i f f m t tcrmr, $1- ~ m n r t~~ .i Churchland, c he anticipates no close march h e m !he folk and rhc wienrik i m g u . But un. l k c both Churchland m d ~~3.r. he holds th. gmdnes of the folk h m c v a r k to kmrbl~hdi~d~pnd~n!iydpnkululr f a c t ~ c o m r m i n ~ i(wmrntinncr hr pmw i n g and data rtongc. Roll up and plaa your ktr
3.2 D i d o n
*. CAUSU. W
N $ AND umRm CAUSES
Why klimthat fhr folk ~torirrneed i n n o echon t o l+timtc them?Th main nuon, Ithink, is ihc i d n that m n r Ira identified in foko;plulationr) m w l bc nraightfolwrrd mu% Any enuinc mlisr wnirming ihc mental, rcmrding lo, c.g.. Fodor. 1987. p. 12), mun seat mental m t r r rr c r d y patent. Svrh -la must m a k thiny h n p p . Any gmuinc rindicalion of foil p m h o l o g mua thus show howthe mental stam i t namn have c a u l pmnn.~ o w d xone , might rrlk. couldmy be1ldth.t the b m id ~ h i l l d ~ l amysoingto in the fridge? Only, S U ~ I ~ ,
5s
CHAPTER 3
/
PATWiNS. CONTENTS, AND CAUSES
dcpreaaion). What thc Various covnt~.hmulsdo is to highli@ thsc rcgularitin ao as to help junify our ur of simple uniUy labels IN& -the emnomic dcp M i o n " or "the b c l i ~thaf f i t is rlining") in wmc qlanarorv mntert (and w Box 3.4 far 1 related p r o W ) . This is not to ray, ofmum, t b l rhe aatim of -nerd quation is itslfunproblblcmatic I n pmicular, we ncrd to be much c l n m (trr *ion B following) a b u t what dirtinguirhc. s ou.of "genuinebut urnnerd" avution fmm the uw of no u w t i o n s dl!Bur the piourr nf-lterd a u r n a lunmainmins the lid h r m n aural d n i m and rdmtilic n o r i s concerning ml p h y ~ i dfmn. d ~ n d the image 61s nicety with mmt work (.LC Chap1~11+a) on connmionirm, MIlmive rffrct.. cmrrgmcc, m d dynamic ryncrns. I t is, in m y cwnt. i m p o m r to be as clrsr u p u i b i c concerning what ir being claimed r h c n we say that b e l i d arc aomrhow ml y n do not m m p o n d la 'lhinp" inthc hud. Dennett invites us to treat t h m sr abrmcrr Bur we m y wonder i f lhc ml i d u (*c, e.g.. hnut. 1987, pp. 71-76)irn'f that l y mey k rrnnnulwtmtmt(suncr.d.~rhp. nor just inside the skull. but even rmu the b n i n a d the worldChopter 8 and commmtr in Dcnnm. 19%. pp. 134152). B. STANCES
Dennm'r anmpt to l i b m t c r a m m o m v psychalaglfmm f u l l - b l d d €odorh n &ism while avoiding C h u c c h l . n d - ~'diminativirm"' ~ i m o l m one w i l y mirundmmad r l m m t , vL. the appul to m intentional ~ n c The c idea, sr wr uw, is that hce a b u t kliddairc. and ra on am only fsrw b u t rhc tendmcq ofmmc o b i m ( t g . r m n , or a cnrl to summb to a m e i n intcrprektivc appmsrh, viz. an rppmach that t n r Lhe ~ objm sr a ntion.1 agent and rwribn to i t bdicfa a d d a i r n (for this naran, the poairion is sometimn uUcd .aurip. ti~un"1.W h t makn aU thi r h n u talk superficiallyuncomfonablc, of mum., is the staunch rcdia inNtion hat my having ccnrin belie6 is logi~illyindcpcndcnt ofanyone el* IrmsUy or p u i b l y ) finding i t &I fo swribc them to mc at all. Canvnwly, i t loolu--hom the amc strunchly realkt pasition-re i f sommnc might find i t w f u l to a s c n k ro meJ!a kinds of b e l i d thrt 1 in ko do not haw. inn w long . I this help than to predict my bhrvioc (just u ideas . h u t n a t d oynal sphhelped wmc P.DP~L pndict utmnomicrl mmu, dspite proving ultimrtclv hlrr). (Mis)lakm up u n axriptivirm. Dana'$paition rcminly ronfmna pmbl m r . Apan ham thesheer mvntrrintoitivcnrvaf ihcpmpaul, it In&to dl ronr dinrcrnd pmblmr. Thus Ruddn-BJm (1994, p. 3361 notes that Dmnm, like the lrst of us, "take bclida to provide xmnr that reux us to behave one w y
~amrns. contcon. and causer
57
CAUSALEFFICACYAND
..~
PROGRAM EXPLANATIONS
..,<..
~" .
~
-
l6,, l%B,
..
nopnevu F d ' e coughing, m y q l m r t i o n hat cites 'aomonc'a cougbhgs must be falw or imcculuc. This would k s m i n h i n m h ar the httcr crplmation amany fulfills a spo.l purpoac; i t makes t r l n r thrt thc condunor would haw (muntobmully) k o annoyed wh-coughedit jvn w happned t h a Fredxu tk culprit on t)ut day. Thee ie t h u ~ r vdu. r able mam g m d t y bougbt by wratmg ths mlrm (Fred) that p m c lpcd m I+X e-i a d c h u 1 - h md Pcmr call q l m a n o n s thsr thus inmkhieo lnrl p k ~ o l d m ' p m y mm l n u m n r ' ~ c r h a ythm. !k folk explanaltonl am 8Od progrun exylmr~onl.l o ray rhll Y c p d ~ d I k x u r .he bc:med i h r v a in ur ohrl YIDI ~ i r one ~ ~of m own. add&yof m m p l n inner s u t a rhmunjvng f a t u x in r h l l thcy all dve ~c m thc kn& o ( ~ & cbduviotd pmfilc we d t c with bcLicving y. l l ~ folk c ante of hlieving y ir t h w out dcpir*rd sl a simple aux but a I plrceholder far a rhalc nngc ofmicrorrmctunl pmibiliria with 1 6 " M d P P m itbl thc folk-& A huther option i. to pktr out whole r m p of micmsrmmal W b i l i t i c r but to inrut h a t in
.adoing~isdumninguursineunlyth~unulamu.F~r.Oruuu~~. it ma, bc srgued. huldonr by p u p i n g t&er nriaw i n I M c a inlo more & M I''muhIencc d-"1 and favrinz anmhon on the common k d l y &df thc "aimm c l n k n Foik &ol*ul Ulk b thu. on. wwith,e~,thcundanth.t*vnthrm~iothcn~Jethrtavredthc .. hanh~houldnra~indnthx~tb.uuvthrpisonw,infict,mprhmine thm thc f o m q b 6 o n ir not pmprhl c a d but ir d y (u
uw
Imom -3 put it) b d y rclmat m a i f wt &acinut' (Julann, 1% p. .%197)1One r-n f a ao doing is. tnr of"many awn: We doa'l wnt m h thu m m n e died horn bath+inc in& nndpiwnin& O l d o w l For.thomugh diwuuion.w.lrkurn (1996).
CHAPTER 3
18
I
P m r . ConmIs. and O v v r
PATTERNS. CONTLNTP. A N D CAUSES
.
..~~.. ~~.~ . ~ h ~ ~ ~ h m ldrDmnctt n d am, vc anw, ofonc mind in doubting that the narasci".p.,-........-.
~~
fans wiU prove ~ompn@lcwirh the full-blown Fodorian id" of inno mbol *tin@thrt replime the nructum m d conrenu of fak pwholagiul m m l i l a.t. .wcimionr. Yrr Dmnrtt holds that k l i c h are rt rul 2nd lcgilimrc u eonterr of gravity a d ~ o n o m i cdqmsio-absmm in good standin, while c h u d l m d holds klich to k u u n r d ar alch~miul -
19
l%is b r nice quation and one that donandr r much mom cnnuive dimsi o n than u n bc pmvided hoc. Some d l quatiom to conrider might h I u & d o n thc (puutirc) r u t t e d uuw figure i n r wide ramp of rffrdiw predictinns rauntnhctuilh m d crplanations?Doer i t fi~urcin m y h d of onirulatd thmy of8 domain?Docs it d o w thmris in om damsin to k l i ~ k d m thcaria in 0thdomains?D o n havemy p i t i v c raronr to rrj.rtthcdaim ,ha, m hem confront n u w of sanered caution? And MI on. The folk diwourr a r t u d h ~ m mthn well in the hu of rvrh guntioning. .bFodor insists it d m indeed mppn a wide r a w of prrdiction~counurFsr-
R t h than ~ rnothcZ and cim M m r t t (1984, a p t " 2) rr evidence. Bur, she a*i f bdick are m haw such uvul &uq t h y -not bc "merely n mdepmdmt," but muat inatead k mlfnturrr ofthe world, i m r p n i v c ofmmpne't pb ,i,l prediaiv. .mr.-gia. 0 ° C wry our wadd bc to su,u v u 1 &iw rs itwlf. ~rancc-dcpcndmtfmrum. Rut them is no r i m that thi, ir M n m ' s w i s h and hir d i m a b u t a d i r y phpirrl phrnommr wcms to point the other ~ ~ d d n - B a k thus er m -r Dcnnctt ~ f w i d inmnsirtcnucr ~ ~ ~ ~ ~(for~ othcr d -,lrr s e Rudder-Ed.. 19941 in hi. we of the idea ef klich, nr u nmer-
Nab a d exphaiins. I t implicitly v k a fairly deep md m i & t d
I
theq
of daily behavior, I t allow throrics in rwi.1 p y c h a l ~ economia, , poliriu, and Iooolog to intcmlatc in wriovr wap. And, pa* Chu~hlmd,IM no paitivc &dcncc against i~ There is, of mum, the apparmt lack of n u t i n n n b n i n state dimdy corrnponding to thr folk it=-bur thlr i s obviourly p o w k r as Nidm- a p i n r the h a g ofthe fok item8 s~ rurterrd auw..
i
~
The inanuond namz rr wu. works for dl *In& of o h m and syslrmaomc rnnretnlu~t~wlt mlentand ih=nonhrrs.Thc h u m i s asmbd t h c d n ~ r c l o f e ~ d a cold bm. the ul lo End a mom, and ihr dnk l o suv rtdi and sumon !he - ~nolepapcr! The rppsmnr p m m k v i v of the inrmlionil stance hrr vorried m y mmmcntatan, m d righllyro. h h l y our preferred rcmnslrunionof Dennm'r position n r kind of rralirm a b u t smnned mum look to k clrsrly ronhrindim r d by the ac
r ~ . a f < n u " . , u , .ha", . m n q i h . r ihn'~h,,y,"~,nl.ndput.r an= d. thou* m m s b n m to b. rurr BUT nonc of u.u tm@ to uhg ihnf ml. w he irmped an h e mx of IV hl ' ~ i h 8onu.d .od L m w a w n #p o r my the pmpo~itiond ltiludm?( C h ~ w 1539, ~ b p.1261
The k
t c a p o m to bath Chumhlrnd and Ruddo-XWer b to abandon MY that human m m u l s a t e am m c d y ~ n u d c p m d e n tMantaliptic . &acourrc, a8 Dcnnar -tedly inriru, picks out mll h m d r in the fabric o f u u u tion. Wc n d not, hmrver, think that such threads must &ow up sr neat i r r M in m inner " c u d monomy. lnaead, m d fo!lming the &mion in the p r d o u r &on,nmayust the mcntrlinic anriburionr rr name for sanered u-lhrt opcrslc ria s mmplex web of stater distributed throughout the brain (and, prhap. the k d y and xorldChapten 4 thmugh 8). Thu ,-nu cxpioltl the ha, n r d y noted by Ruddn-Bahn (1994, p. 3121 Ih.1 "on= co*ld k a reallst a b u t k l r c i and idmnfy r bcbcf n t h complex ma of w h i m rood the cnvl,unmm~.' 7hr nmhlrm.. thm.. b to d~stinmihthe id" af klicfs .r wanend uurer h "spin1 plmdingmmd "ili.mofivned pro*-tionim." When b r cause m l bur wrttered, u o p p d lo not being red rt all?
,-tion
~
4 '1
i
~~~~~~~~
i
CONNECTIONISM
... . ... ., . ,,. y * h " 4.1 S k e t c h Thc ~ ~ m p u u t i a nview r l ofmind cunently coma in nro basic vmaia. The buic phy.i=al symbol ~ ~ r m n t i celready v, mmunrocd in Chapter 2, .wYr TO.I o i ~ b astom5. ~ i ~ISU=IY) wris1 pm.euing, m d m p m i v c m u r r n whorc mmbinationd forms c l m c l y p d r l ,how ofl m gmge m d logic. Thc athn main vaticry diffen dong ail thrn of 8h.w dimmdonr m d is h a m variously u mnncrtionism, pardIcI dii~~ibuted pmming, and anifidal ncunl "elm*. Th- later mohk, m thr 1st name sumes~r, .. bnr romc (admittedb dhrrahcr distant) relolion to the arrhitcm~nand rnrkingr of Ihr biolo@calbrain. L i i the bnin. sn mifidd neural n-rk is < o m p o d of many simple pmeuars linked in psnllrl by a daunting mau ofwiring and ~ ~ ~ ~ ~I ntthe mbnin, r y the . "rimp l prxrmon" ~ are neurons (note the quota: ncvmns am much mom mmpler t h m connectionist unit.) ~ n the d conneeions are u o n s m d s p a p e r I n mnnrctionirl onwork thcsimplc procenom arc 'aUed 'units" and thcconnmionaconrirt. in numctiullv wcinhtld link beween thee u n i r d i n b horn. unimainn" t i d y hut ~ 6 t hpinpoint accuracy. IS mnnmionr. In both c-. ~ h csimplc p m i n g element$(ncumns, units) are generally wnritivc only lo Idinfluencn Each dcmcnt t d r r inputs ham IMU p u p of k i g h b o r i and parxr outputs to a rmdl (mmetimer omlapping) group of ncighbori ~ o n n e ~ i o n imodels rt m d ml n m n l -hiThe diffenncer k t m n l=Nm remain immcnrc and we ,411 mvim romc of them later i n this
e.
!
.
I
tI
N E W (%inowskiandRosmkrg. 1986 19871isan anificid n m n l m r k . mated in the mid.19801, rho= hsk x r a to nke vrincn inpuc and turn i t into coding for rpech, i.c., to dographemc-to-phonm conmion. A surrrsth~lrlatr K l l pmgnm, did DECtak war already in exirlmu and performed the u m c tlrl counny of r la*? datlbarc of rules and ex~cptionr.hand r o d d by a tram of human programmers. NETtdk, by mnunn. instead of k i n g nplidriy programrnd, lrarnrdto solve thc pmblcm using a learning algorithm and a rubtanlid corpus of nrmplr c a u t a a u a l instance of gmd tut-ta-phanme pairinw. The ovlpvt ofthc n c m r k was then fld to a fairly rtmdardsprech s p t h e l c r that took the phonetic codingmd tnntfomed i t into mlspeech, During learning, the r p - h output could k h n r d to progres h m inilial habhle to xmirccogniuble m r d r and Iylldlc rtrurmn, to (ultimately) r fair simulacrum of human spmh. The n-rt it should he mphrrizd, w s not intended 8s a model of lhnyag understandingbut only d t h e tat.to-8pcch transition-r such. there wu no rem~nlicdtitabswtiedtothciinguislic~ruclurcr. Dnpiteth'ubckofsrmmticdcprh. the n m r k stands ar m imprcsir. demonslntion of the power of (he mnnec. tionisr approach. Here, in briefen oudine, b how i t worked. The rytem. ar mentioned above, is comprised of 1 ~ c oft simple p-ing units. Earh unit mrciws i n m e from is nridbors " .lor fmm the world. in the au o f ro-cdld input units) and yields an output according to a rimpie mlhrmrtidfunction. Such functions a n oRm nonlinnr. Thi mans that the numerical "due of the output i not d i m l y pmportianal l o the sum of thr inpuu. I t may b,for nrmplc, Iha r unit ~ i v aopmpnion=l output for an intermediarenngc of lam1 input value%but givrr r tonsonf output abort a d k l o w that range. or that the unit will not "fire" until the inputs rum ton certain value and thereafter xi11 give propordond outputs. Thc point, in any uw,is ihsr a unit became a&n t l d ro whatever d(if my)the inpuu h m its 1-1 neighbors dthfr, a d that i t wiU p a s on a signal iccardingly. I f unit A xnds a signal to unit 6, the rlrrngh of the signal arriving at B is a joint function of the lrvel o f activation o f the "wnd.r" unit m d the ""mcri~dweightins to the
-
..>~,. ., . ~ ~ , ~ . : ~ , : . : : ~ ~ : ~ ~ ~ ~ . v ~ . ~ ~ y < - . ~ : : ~ ~ ; : ; ~ , - > ~ ~ ~ . ; ~ ~ - ~ * , ~ , ~ ~ + ~ , ~ < 9 ~ " ~
~ n ~ r p s d k ' ~ ~ d ~ ~ r m t ( ~ ~ ~ ~ ) & i b a ~ d
+I.
but by ao Wm).'Ibe fiml~rnmpriudaMof'~f~~wh~tnl;*umd~thcd.u m be p m d (information hh a qmur).a - n d +r e n ulib (8 hpiul * h - p o d o n '
drteddapuPof*ralledhiddcnulihrhorrpbwru,&maput*l moding afthe inpn &tr Thc l h i la^ condnrdof'outpuf mib who% xtintion pa""", &maim ,be ~ y " mo ' ~ d rapom ro Lhori&d in-
p~Thirrrrpmr~rpdMurrmerofnumaicllMin~innnlua.om nluc for ..rh ovtpvt uoh The Laow!dge that Lh splem u w t o yjdc Ihr hpw-output lnnritioa~L%thw cx0d-j to a Lrgl m a t in Lh ucigbu on the n r b w inmunit mnnccdonr An immrtmt hamre of Lh mnnmionut appmwh iia in the us of a *mm of mml l t h o v b bi no m a n om~ m U lrrmiog 1 alp, n abd aor 421 rdpaLh-&uonthc d d y bring the wrnll pefonnmeinw ut f m c h n h p lid1 inrbadyofIdmgcu
MrVT
TEXT:
h to fmd thc bane-the paint m n e p n d i n g n, thc lmnt o m m d hcoz the bm milable rolvtion But you ur blindfolded m d -01 we thc bmrom uud -at run dirmly re i~Instead, you &I a single rtcp m d delermine whether you wmt up or down. I f p u wrnt up 1%loo1 crmr). you p bx* m d ny again in the opposite diredon. I f you m r r dam, you rmy whs, youare. By rrplring this p r d u r c o f r r m l l slrpamd I a r l f n d W p u do+mrle lowand the bottom aod t h m you halt IJinccno furthn rtep c m rJ;c p u any lomrl. Thc I dftcdbd, in h e uw of thc n w n l netw o h ia prwided bythe mpcrrirory agrlcmrhat dernmim whnhan 68ht in~rcau or d e m u in a weight w u l d impme ~ r f o r m a n c(ruun. l
cm
the other weigh*
m a i n fixed). This p m d u r r , - 1 4 -ght by m d layer by bpr,rR&ly p w h a thc qstem d o m a d o p of dc c m i n g m r . I f Lh lsndvrpc is a nke pudding-basin h a p with no nrrry ing
Lmcr (in ~nglirh)nrier wi&ly rccordingly to the sunaund'mg 1n .lk input mils wee conncrted to a l a ~of r 80 hiddm unirr m d l h u r mnnerted in fum t o r rct of 26 autpu~uniu coding for phonmr.. ' f i r total number of Internit l i n k in the ovcnll n-rk summed to 18.829 wci@thlrd connmioor Civcn lhis large n u m k of connections. i t would b. impnrticd (lo rsy the Inst) to M about finding appropriate intcrunit sonnmion wcighu by hlnd mdin& and trial and rrmr! Fonun.tcly, ~ ~ t ~prored~rer ~ n i c(laming dprithnul c*n far mnins ulc wights. 'rhc ~ r famous n (but probabb biologically lcut rrdirtir) such p r d u r e is the m - c a l ~bark-propaption lamins algorithm. I n back-propgation ielrnin&the -orkb.@~with a yl of sclmedmnne~tionw~ight. (the ~ h ~ ~ t . ~ ~ m b c r ~efa. ubeing n i t rf , d bythe d r ~ @ n l .This network i s then .rpawd to a number of input pmrrnr. For rach input patam, aomc (initially i n c o r n ) output is produced. An automatic r n p M ~ o r vy trm monitor. the output.emprrr i t to ihr large! icorrrn) ourput. and a t u l a m m a l l .djunmcnfr to th. mnnrctian wighwdju.rm.nu thu would ravw slightly improved p c r f o n m v c m thc network to be reexposed lo the very almc input pattern. This p r o d u r n I= Bur 4.21 i s rcpatrd s p i n end again for Isqe
66
/ CONNEtnONlSM
CHAPTER I
i m d cycling) mrpvr of tnining na.Ahm sufficient such trainin& t k n-rk ohen (though not almya) Inmu an usignmcnt of weighu that .ffmiurly -1the pmblc-nr that ndutn the error signd m d yiddr the dnired inputournut omfile. Such lnmingdgorithmr ran d i ~ m a l u t i a n s t h s we t had notimrgined. Re. searcher birr is thus somewhat d m r r d . Momwr, a d p r h a p mom impormdv, t k wavthe trained-UDn-rk rnmdrrthr moblm-mlnnrinformafion is quite unlike the nnort traditional fonnr af *rnhIutring encoding c h m a c r i n t of ihc work dirluscd in C h r p a 2. 'The cannectionirt ryrmm'rlongterm howl. dp h e d m not conrin in a body ofdrclanlivc natemmtswinrn out in 1 formal notation b a d not on the rrmcmrc of language or logic. Instead. thc h o w l d g e inhe- in rhr srr o f connmion weight. and the unit rrchirwtu~.Many of lhne w i g h t d cannmioru p n i d p t e in 8 hrge n u m k of the v t r m ' ~prablcmsolving aaivitier. m u m 1 h o d e d g c t h c information active during rhc procaring d. ~ ~ e input-mey i f i ~ uwfvlly bc with thc tnnsicnt activation patterns acurring in the hidden unit irycr. Such pnernr ohm involve dimibntsl m d suprporitionalwiing whcmrr. T h e rrr powcrfvl features, rn In's pauw to ""pa& the jargon. An irrm of infarmlion ilhcrc said to have r d'rtributed rrprevnntion if i t i% a p e d by the rimultsnmu8 activity of a n v m k of v n i a But whr makn d'libuted r c p m m t i o n computltionally p l a t is not simple la" don+ but the syitrmnic urc 01 &c dirrributionr to encode fo6th.r informstion conmning ~ubllcrimilatitinanddifferencn,A dirlributd pnerndtrriviqcan rncodc'mimtrutrural"informafian ruch that variations in the ovcnll prnrm rcflm -tiations m the content. For rumolc.. a ccndn oattern michr rmrrwnt Ulc orevnrr ~~of a b l x k a t in the visual field, w h e w l m d l variations in ihr p a l m may a n y information about the cat's otimtatian ifacingahe8d. side-an. nr.).Similady, the activation p n r r n for r black pnthcr may sharr ramc of the subuu~turcof the at activation pa,. whrmrr chat for r white for may share none. Thc notion of upcrporitional r ~ o n is g prcciwly the nollon of ruch panially orcdapping use o l distributed mourcrr, in which thr o m h p is inform8tionally rignifiant in rhr kinds of way just oudind. The vphor ls that mn!i
.
.
~~
~~~
~
~ ~~
~
.
.
" .
~~~
. ~ . ~ ~ ~
-
the ability lo pmduce mriblc rnponv~ $vcn am wemi. damgc. Thir is p rihle k c a w the o v m l l system now u t 5 u r Xind of p s l t m c o m p l c t a ~ v 1 nr large enough fngmenl of a familiar panern, i t will mll the whale thing. Cenernliution, pattern complaian, and damage tolcnnce ire thvr all mflmionr of thc u m c p o w h l computation$ arnrcgy the w a f dktributcd, tuprrpoaitlorulstorage whrme m d panial cuc-bawd maU. Tm, furthcr propcrtin of such coding whhcma demand our a(101tion. The fin, b fhcaparity to dmlop m d a p l o i l what Pad S m o l c W (19881 hu I-ed "dimension shifted" repmnationr. The wcond is rhc aptcity to display fine grained conten rcnaitivity. Both propertin am implid by the popullr but opsque glos on cannrrllanism ih., depicts i t ss a 'subaymbolic p n d i p . " Thc menti4 idea is that w h e n $ bark physic$ symbol w e m app-
~
~
~
,
.
~
~
-
the *em uncamr arc finer grain4 a d mom subtle than Ularr picked out by single wordr in pvbliclangua~.The claim is that thecontentfuldemmts in r rubsymbolic program do not d i r e l y reupitulatc thcwnrrp=wwr u w % mnwiouk
.
~
63
CHAPTER 4
/ CONNECTIONISM
The wlucion lo hpprhim of 'pnnnlnnng aalpirv 10- u, the urc " l a nnm, of tmls m d irchniques ~nrludingstalm!nul analns ~d mmmtV inwrfn. cnm. s ~ e m a t t cl n l d n r n r c rnroivn thr d ~ h b m r cdamlcma or dotrudlon of - ~ ~ ~ o p u p s of unit%wn ofwighrr, or interunit mnnmiona observation ofthe Mwork's "panleion" btha\ior cm then pmridc urfvl cllvr m iu n o d owr.ling atrslcgier I t can alro pmridc I funher dimension (in addition to brute pdormancr) alongwhich tothe "pychologiul nrliy of. mode1,bycomwring thc m y the ncmnrk rnns to drmagc to the khahavior p s e r n s =en in hu. mms suffering hom vmrious fomr of local hnin damage m d s b n o m l i ~ (uc. e.g., Prtmon, S c i d m h , m d MelrUmd, 1989; Hinton and ShaUiu. 1989). I n practirc, haw-r, Ulc mon -ling form of ponminingmdpia ha- i n d d nor anificial laion n u d i a but the n u ofsrotiniol cmlr (m Box 4.3) 80 genmtc a picture of the my the nrmork h u l r s m d lo ncgolhv the problem space. So far, Ihm, xr haw concmlntd our attention or whal might b. t m d ofint-gmcration" connMionist ncfwork 11 would b t mirlcading to condude. ho-r. without offering at iue a mu@ *etch of the r h a p of more r e n t drveiopmenrs. Smond-gmcrrtian mnwlionitrn is rmrM by m inemring -ph=is on t m p o n l structure. Fint.gmmtion nnwo*r, i t is fair t o u y , d k p l r ~no mlcrw i l y to deal with time or order. inputs that deigmtrd m ordered q v o l r c of k n c n had to bc rendered using r p c i d coding whcmes thrt mificlnuy diumhigurtd thenriourparribleordcringr. Nor wcrcauch n m r b geared to the pro. ductbn of ourput palems e r t m d d i n lime (r.8.. the q u m c e of m m m & needed to pmduce s running molion)' or to the r w w i r i o n of tcmpanUy atcndd p a t m r w h t r thcrequrncenofM.1 motion that disringvirh a m l r m i l e fmm a g h m . Insteed, the neworb d i s p l v d a kind of"snrp%hormroning" ~n which s fmm Impan1 instant (cg,coding for r picmn of a smiling person) yirlds a ~inglcoutput repans. kg. r judgment that the -n is happy). such nmorbcould notidmtifyan iostanrtaf plcsrant ~ u r p r i u b y p c ~ r i n g i h s g ~ d . ual tnncform~tionof puulcmmt into picarum ( sac g . Chumhiand, 1995). To deal with such t r m p d l y mended dam m d phcnomcna. mond-gcnmtion connmionut r u s r c h m have deployed sa-crUed muncnr neural n c h o r k . T h e n c h o r k aharc much ofthcnrvctureofa timplethrre-layaersnaphot"n a work, but i n c o r p r a s m additional feedback loop. Thii Imp (we F i y m 4.3) mWcr lomc u p c n of the nerworb miriv 11 time 1, siongidc the new inputs uriring.1 fimc h. E1m.n nrb (wc ELmur. 159lb) rrcyclc the hidden unit acriv.tiw pnrm from the prrviou time slice, w h e w Jordan (1986) dewribn r net that recycle in p-iour oulpul pattern. Eithcr way, whal ir prrwrvrd is w m r lrind of
CLUST
as" .n*sir
is .naumpk of m lnwc ,M* add-lq ibc aurid qusfiousfi %hat kinds o f q-ndm hm the mwo* aquird!' A three-law n-rk wh u NFXbk w the hiddm unir bpr to Pufition the inpuf. lo u to mmand dilstr the inpot qrrrntation -in way r i t d to th. p & r m e t function implied &themining &trT h o s i n t m - t o - p h a m c m n n n i m m n tt h e ~ r h n d i K ~ mwn it t ten i n p u ~ '&"d 'mil' to yidd the a m pbomic outpur Thc hiddm uniu should thua mmpm. thuc om inputprncmr imo some m m n in<-&at. form. lnpuu such as 'ahape" and 'slii" sbouldmdve diflmnl theugh nor unwhted, c d i n g s w h m u "pint' m d "hint.' despite subnantid winen orerlao.. mmivc wi&b variant nhonmic m n w and rhould b t dilsred-pund further apn. To @arm t k iridc. ofpulling together and purbing *pan, NET<& dordopnl79 diffrrrnr pmcm of hiddm w i t minq.Uuner anwk thcn inmlvcd flldng e c h mch p a r r n and matchinsit with in m r c r t "~ighbor(e.g., rhc four-unit a d m i o n pmcm lolo is n a m to 1110 thm ra 0101. &ce thc m n d d i f f m from the fin, in only one p h e wheres the third differs in four). The most cloW matched plin arc &en r m d n d (by r pof n d o r arempingl u n w single p n n m aad the comparison p r a a . is -fd. The pmced- continur~until the find m dwm ur gen-14 reprenting the-ldirirlon of lhc hlddm unit Iparc learned by the mrm. Thc reuit is an unlabeld, himchi. ol me of hiddm unit sr6viry The mrt mk is to lahcl thr nod". Thir is d m r 8%follo*r. Fnr a r h of the n w n d 79 m i n t i o n parema, the d y s l rr(ainra tncc of the input pmm that pmmplrd that s k i f i e rnpanrr. She l a o h at the prim(or pin of p i % nc.) of inputs that thc n-rk 'chmc" to .uociate with there similar hiddm unir x r i n t i o n p n c m u,as todiscem what t h e inpuu had in mmmon thrt d r it vrfuifor ihc network t o m u p them togethth... Ihc nult, inthc-of NEl'mlk, is a bran&in.h i m c h i d tree 1- F i m 4.2) whau: erd i k i o n into the Inm i l i r groupings ofwvcls m d v l w n a n a m d rherubdivirionr h d u d r groupin* of diflmnt m y of aoundimgcmain input hnen such pr i o etr I n hrt. marly d the p h a h groupin@ lnmed by NET1IUr N m d out lo -pond d a d 7 dye d i m in mating phonetic theow h e further fnNR dim& in Scab" 4.2 is that nriovr vmionr of NETulk (mainbiningthr rvnc d i m r e and l m i n g rovtine m d mining data but begin"hgm+th dii-l ~imgnm.ofrsndomnighl') orhibit&, &" tninmg
wid
.
urn
*
70
CHAPTER,
CONNECTIONISM
is-.
I
INFVTUNRS COMUT UNITS F I 4 . f A f h - l r ~ m u m , " m o , k . T h . ~ r n r n " n i l r r r r m i n ~ , o nby~one,by Ihc mnnprdins hid&" uniu For orimp1iriC7, "0, .U th. ,mnmn b shorn. l M r r U. mm, IWIb. r i t h prmision.1
Phm*lH~lrhial~.nWi.dm~rrngvminWmkbi~ uniu for ~h IR~CT.~O-YIY~ m d m li-pfa h r l m d p b o n m pl. Th. do* h n h n mnnpond lo the moll nruly nmlr &tionrrrrors of itr hid. dm mitt (Fmm S+ndimO RnrmncR. 1987, Pamud nmmhrthat lnmtopm noun- Englirh *XI.Cvmplr. S p l m 1, 14s168. Reprad~edby kind prmiuion
on-ping t m ofthc n m r Y s last rcfivity. Such -t ad ur kind of rhon-rmn mcmorycnablin~thc network to p m t e new responses thrt dcpcnd b l h on lhr current input and on the previous activity ofthe neworC Such r wt-up olu, 011output aaiviq to continue in the mmplote r b w n u of new inpas. since the n ~ o f can k continue b ,qlc if, prMovr stat. rnd rr~pondb them. Farexamplc, Elmrn (1991b) k r i h e r r simple mcvrmrr n n v o r k r h m c p d ism calcgotirc wor& acmrding to lexical role (noun,verb, nc.).The n m r k rn e x p a d to p m m a t i e l l y p r o w rcgucnccr ofwords (such P 'lhc b y broke thr windov"l. Its immdiatc task xrr to p d i d the n m word in the an-going xsucnu. Such a task, i t should k dear, has no uniaue lolution inrohr as man" continurrionr will k pcrfmdy acceptable gmmmtically. Noneheleu. there are
whale c l a w or war& !hat c a n a l k allowed to follow. For cxnmplr thc input wqucnm "the boy who" unnot k followed by "car" or "tm." Thae conatrainw on aruprnble sumruor words rcflnt ~ m m a t i c amir l and the training regime thus pmuider h r a g c m e to the larger 6 4 of lrrmmin~a b u t lcdcal ut%otirr. Elman's n-rt proved filirly rdcpt at is WL Ir " d i x o w d ' carrgarirr such P w r b and noun and alw, cvolvd grouping for animate and inanimate obimu, fwd.. md breakable objerra--praprtin hat wcrr good dun lo gnmrnatical m l r in the mining corpus used. To delcrminc exactly what lhc network lcrrnrd. Um m uwd anofhcr kind of pontnining malyir lone bencr m i l d to the iwid ow of rrcuncnt n*sl d c d "prindpd component snalyir" (PCAl. The durilr am giwn i n Clark (1993. pp. -7) and ned nor dctrin us hcrc. I t is worth noting h.rrmr, th* ",ha rlultn .n.1yir o n make i t rrrm i f r "mr0.k h a mocly 1car.d 8 set of Detic d'ir!ributd qmbols and is thus link more than a implcmenueonof hehcdruical ~ ~ ~ rompanmr t i p l l an+sur resu-ful khavior. The key veals !he mle of even derprr dynamics i n ndex ir ihzt whereas rluvcr mal,un s t r n rc'atnon. ~ ~ ul $ ~ m ~ l a n and n dnR~rmrr k t m n q t n r t t r n I"smpshot%'l PCA rcHms ~nadd toon the my in whrh k'"8 ""t ,,ate I,". "
-
,"
7'
CONNECTIONISM
CHAPTER 4
future states Sandad d u w anslysir w d d nor mnl thac mnslninu on pm-
-ins
tnjmorin. Yet the g l m m t i n l imodedgc -~i.ed by the rrcurrrm n n inheres qvitc profoundly in ruck trmporally rich infmation-praesing detail.' Thr more such t a n p o d dynrmia manth the funher we move (1 antend) horn the guiding i m l g ofthc basic physical symbol a y t m hypoth-. For 11Ute hnn of that image lie thc notion of n u n w y rutic rymbol r t r v n u m that rct a b ruble mraning while k i n g manipulated by romc kind of r e n t d pra-r. Such a piclure, however, d m not uwfvlly dnmbe mc o m t i o n ofwen the s m pie rrmrrcnt n m o r h prcvioudy dircuucd. For the hiddm unit anintion p r tern (the nearet nodegue to stetic n(mbOIs1do no1 fundion u b e d rcprucnutiomof wrd-mls.Thir is kaurceachru=hpattcrn rdlm.romcrhmgof thcprior w",.R,' w, that, in r mu, " e m accumnu of. ] < r i d item h u a -.m,r in. r r m d rqrmntotion" (Elman, 1591b, p. 353). Elnun's model thw w ro.ulled dynamic rep-ntltionr. Uniikc thc clasial image in which the linguistic agent. on having a word, mrin kind ofgened-purpoo. lexiul rcprewntanan, Elm m is rmacning r dynamic picture in which
mrpmpori,ion.Imndthnr infamutionma.nt~bmgn.on.~dywitim~...w* m u guidvru which ~p msblikhnxntal stntn that Nppn ( d n i d ) b r i o , . (Elnun. 1991b.p. 3781 ~lmsn thus imitca us IO w. b n d thc d s u i o l imp of natir ~ b lthat r prsiat u stared tynlrdc i- a d thrt arc " n r i w d ' m d 'mMipuhtrd" dur8ng p-smg lnsmd. r confront in ~ m of p a Ilutd tnno ~ o n o m um whrh wrrsmlaroonr are ~onrrmcledon the ,pol and in llgllf of !he plollrng urnlrn and in whrh much o l ihr mlormzt#on amvu8nc o # w n resodo m in. r x~, \ cur ~-~ rent ~ t r t constrain n the fumrc lrmponl unfolding of the rynm. mid-gmcntion a n n d m i ~ m continun thY flight fmm the (natic) inn= rymbol by laying wen greater $muon a much wider nngr ofdynunic m d timcinvolving p r o p n i a For his m-n i f i 8 romaimn h o w sr . d p m i o l a n n~tionirm."D y n m i a i connmionirm !*Wheeler. 1994. p. 38: Pon and van Gcldo, 1995, pp. 3 M + I introduce a n v m k ofnov and more ncumbiologjally miiaic kafyrfyfyto the hadc uniu m d weights paradigm, inclvding spcial purpou units "nola whou m m t r o n function 0% tailored lo a urk or dunwon murc compln y lmuncnt c p t h w .nd s ~ upurpov l winng), romndl.lss~nds vlmnsl i~~~~r~1rl.n #an dlc n r t r c u o n c r r r l n . c o n ~ ~ n ~ m ~or". r~-~~mr 0 .
~
~~
~~~
~~~
.
&biting such nomndard fir!ura support "hr richer inuinrir d y n m i a thm tho* producedby mrinnrerm eonnmiania ~ y s t r n f (Whedn, l 1591, p. 381. We hall have moremsyaboutthcpotmtid roleofsuch richer and temporally loadd dynrmicr in future chtprcrs. For rhc moment. i t will sufflrr to note that yrondm d third-ecnmtion connmionist mearch ir k o m i n g ~mcmr%ivrlv more and mare dynamic: it is paying m r e h d to the tcmporal dimension and i t is exploiting r ddcr n v i w of of unie m d connmivifl. I n WJ doing i t is moving ever funher fmm !he old notion of inrrlligenu ar the manipvlrlian o f r u t i z rtemponl, rpalially loalilsble inner rymbolr. The conneeionin movcmcnt, i t is fair to mncludc, ir the I==d'ing~ r e s i o n of 9 n n n symbol flight." The rralic, chunky wr-friendly, semmtialhl transpaparn (uechspu~r21 innersymbols ofynrc~mkingrrple~ed byrubclcr,oRen highly dhributcd and incrcr~inglydynamic (time-involnng) inncr states. This is Iklim,a basically bu&bC mndtion. Cannwlionin modds profit horn (increac ing) mntad with mi ncuroxirntific rhcorizing. And they exhibit a profile of strengths (motor ronnol. pmecrn m g n i t i o n ) m d wcnimcrxr (plmning m d wqucntial l&ul derivation) Ihar snmr rauurindy familiar m d nolutionarily plausible. They l m k to avoid, in large m w m , the unromforoblc back. proicc!ion of our npcrimccr with tcn md words onto the more brir biolodal cmnsr of the brain. But the new l r n d v r p brings nov chdmmge, pmblrms, and uncenrinriec T i m to mea the bugbears.
-
-. -
4.2 D i i i o n A.
CONNECTIONISM AND MENTAL CAUSATION
Cann.aianirm,rcmrdingto unnc philmophn., oRrn .mcrerr
..
.
.
future n a t s . sundard cluaro uldysb rnrdd not mul th.n mnstnints en p w ccrring traiaoria. Y e the p m m r i d knorrldge acquired by the mamen; m i n h m r gvitc pmfoundly in such temponlk rich i n f ~ r m a t i o ~ - ~ ~ - < ndmi1.l g The mom auch tcmpornl dynuniu matter. thc further & movs I1 mntcnd) h o m the yiding imrge afthr hrric p h p i u l s y m b o l ~ e r mhypothcris. For *I lhc hran o f that image lio the notion of csenwntiaUy natic symbol rtruflurer that rrtsin sable mcrnin~nwhile Mna m n i ~ u l a t c d bv ram. b n d of -~rentrnl or%-r ,~ Such a picture, ~OWCYIT, d m not uwfully dcurihc the o p t i o n o f m n rhc nmple w r r c n l ncworks previously diwurwd. For the hiddm unit actintion pattcma (thc n-rt mdoguc to rtatic symbols) do not function rr 6xcd rrpmntetionr of word-rolc.This ir bcovscuch such prim reflects mmnhingafthcprior con-.' w rhat, in a *M, "cvrry acurrcnce of s I& t r m h u a q a m t c internal reprrun~tion"( E l m , I991b. p. 353). Elmm'r mcdcl thus ulrr w-uUed dynamic qcrunutionr. Unlike the clsrricsl h a g in which fhc linguirtic agent. on hearing a word. mri- a kind of g~n.4-purpow lexical repmentanan. Elman is rug@ning n dynamic pirmm in whth
"
.
~
~~~~~~
~~
~
n e w u no wpn* m p a f l r x i a l mrionl.Thmomna repenantions o f r o d in mr rrprrrrnl8lDnrof w.da (Ihe in#-1 eta lolloringinplof r n r d ) .Iwa~ mnm Ul* .put t&" f~@h"xith Ulr prior m e . . the rpree ,n ".,it. a* "otpmpailiondlndd.irmfnm.tion
.
Elmm thur invitn ur to we b o d rllc c l s u i d image of&. symbols that p i n u n o d v t a c t i r i m r and that m 'rcrricvcd" m d "nunipultd' durin&pmcesring. Innerd, we mnhonr an imgc o f r fluid inn* Konomy in which rrprermtrtions arc cannrucied an the spot and in light of U. prmilimg mnten m d in w h t h much of the information-p-ing power resides in the wry current s u t n rarutnin the futvm t m p n l ~nfolding of the s p t m . Third-gmcrnion connmionbm mntinurs hi. flight from the (static) inner on r much wider range of d p m i c m d timesymbol by laying wen yam st8nmlnns propcnan Fur lh#\rrawn 1I$ nmnnmo k n n m s~ 'dymamml mn. nmtonam' Dvnlmeal connmmn~rmlur Wheeler. 1994. p 38 Pun m d rm Cddrr. 1995. w 11-34) ~nlmducc~rnvmbcr 01 n w m d mnrc n r u r o b ~"~ l a u, ~ a l l ~ m l i n i c mmms lo the h i e unia and weighs paradigm, including s p c i a l purpme units luniu whaw activation function b uilomd to a tmk or domain), mom m m p l n connmivity lmultiple r m m t pathways and spcci.1 purpos. wiring), mmpurafionally rlicnt time delays in b c p m a r i n g q d e . con&uou-timc pro-ng. analogS@iq, and thr dclikratr ux dnojw. NliKcid n ~ u n-rks d
..
cxhibiting mch mntundrrd fcrtumn m p p n 'hr richer intrinsic +miu t h m tho* producedby mainstream m n n ~ i o n i asyrtcmZ t I W e I e r . 1594. p. 38). We ahall havrmomtorr/about t h c p o ~ m t mlcof i~l such richermdtonponlly l d d dynamics in future chapter$. For the mommt, it will ruWw to note that urondand third-pcntion eonn~fioninresearch is kmrning progrssiuely mom snd more dynamic: it t paying mare heed to the trmporal dimension m d i t is rrploiting a wider vlricty of w of units m d
.
~~
~
0~
~
4.2 Discosaion A. COUNECTIONI$M AND MENTAL CAUSATION
Connectionism, accordingtosame philamphm.offer~n ronrrrtc challmgeto the folk pmhologial image of mind. The Indins idea, anw again, ir that lolk wchologl ir romminrd lo thcousrl cfficncy of the mmrnl s u l n named in ordinary dilroursc, m d that them is now r ttmion hen such imadned u-1 cWcac* and the sprcific connectionist vision of inner pmasing and rtongc. The key move i n thii argument ir the inrinenw that the folk f m n a r l : is ind d edommitrcd to a strong m d d k t notion afcsuul &car).. I n this win. Ram9, Stith, and rnmn (1991) inrirr that the m m m a n ~ n r cunder~lrndingofmind involve a -rid commitmmt to what t h y term "proporitional modularity." This is the dnim that lhc folk urc of pmporitional altitudc talk (talk of Pepr's k l i w i n g h t the wine is chiied m d wr on) implin commitment to "hnojonolly d i m & wmantirnliy inlmprrtn&k n a a that play a m u 1 mle in the production of othcr ~rooasitionslanitvda m d ultim~telvin the oroduflion of behavior" 1Ramuv. . Stirh, and Guon, 1991, p. 204, original cmphadrl. F a r n q , Stich. and Garon nry e that dislrihutcd mnnurionirr procnsingdoesno! suppo* such pmporitiond and hancc that i f human minds w r k lik rvrh device, lhcn ihc folk vision is fundnmcnlllly inaccurate.
. .
..
74
CHAPTER 4
CONNECTIONISM
Why s u m th.1 the folk ur rommittrd to prapmitional m d u l n t Y myway3 he Nidence b i n pnrncvdatd (we do raik ~ f p e opining ~ l ~ or loving klicfs one at a time a d in that m s c we wem to drpin the bcliefi, e 6 , u dircmr item+bmwy, Stich, and Gamn. 1991, p. 205) and in part ruhrtnriw. The rubrtantiw Nidmce is !hat the vy vlrfulnmaf the fo!k barnwork wcmstodrpmd on our k i n g able to cite rprrific beliefs n. explanatory of spcific d m r Pep m y k l i m e h a t the MI w n u fding, ,hat Rome b pmy, and that the vine ir chilled, but m rnrm the "ght to m p Y n her going into the kitchen u a d i r m of h n belief .bur the vine. The a t belid, thou& ml and apablc of the m e khmor, may be i-"d to b. inartirr at that moment. And the Rome belidnriks us ra simply imlcvmr. I n thw highlighlingonckli~f in the crplmafion of PCP's action. wc am mmmitting ourwlvvl, the ruthars srme, to the di. that i0di"idlul bclirfs u n function rs the diwrc* uuwr of sp cilic -ions. ~ h commi~mcnt b riummlortably with the mditiond Lind of hl. modrl i n which a+fic inner synracri. I t r l < o n w n d to rpnfic i- o f inlom.tion pitchd at thc 1-1 of drily &I and mntepu But lhii combination of lnnn dirm i a n ' ~ n d ~ s e m m tranaparmcytic (e C h p m 2) is nor, it *ems lo be found in dilributcdvrnnrctionirt mdcls. Oncmaior r a n ithe onlvone llut ' 4 1 cone r n us hem: for r 111diwusion uc Umrk (1593, C h a w 10) turns o n the wnncctionist's uw of overlapping ("ruprpasi~iond") made of informtion stocagc. TO forus the problrm. Ram-. StiB. and Caron r k ur lo consider two n w r k of which ir trained to give a @no annvcr to the same wf of 16 quutionr. To 01. input '"dog have fur' it mvrt output a tigd for "vrl'to "6Jh have fur.. 'no." m d so on. To perform the I&, the nu must find r ringlc weight mrvix th.1 supports thc dnired functionalin(. .'Ihc uw of distributed stong. tcchniqun (rrr di-ion n b w ) man%however, that many ofthe wighu m d units implicated in thc of the knowldge thst d o g have fur i U alro figure in the <mod. in. of the knowlder " that a t s have fur and so on. Hem,thm. is r. fim l~utativc) mod&"ty. The conflin comcr about k l u c con,lirr with ~~
-
.
~~
~~
.
~mfoma#iomNoded..i.s#oRd hdutically and dinibvnd lmugbour h r nnwrX.Wh-r informtion isnmoed.. nsnymnrraion sam@, nuoybiun and m n y hiddm units play8 mlr. (Ramq, Stkh. and Guon. 1591, p. 212)
.
Thc id... thm, b +hat the uw of overlapping storage lads to r kind of i n n n mush such l a , u far u thc innards are concrmed. it is no more ddrnrible to uy thst the knowledge that d w have fur c a d the mpmse'yes," than to wy t h r the UUK was the knowledge that fish have giilr! This is the rhrert of whst Stich
(1991, p. 181) once t m n d raal ~ u lh o f l h . Total u d holim, ilshould be el-, i. no, ptim hri, romp.tiblc with ,h< idea of indiridwl klirhas d*< --.A -d c,pes of conflia (Rsmuy, Stich, m d Garon. 1991, p. 213) b r r vrrled i f w rompare rhcatigind 16-propotitionnuto anothnnn tnined on one r d d i r i o d item of knowledge. Such a 17.prapaaition ncn*ocn*ok acmmmdatt the additional howicdgc by m&ng small changer to a lo1 of wcightr The folk Y . a lot of mmmonriiy h - the wo mas. Both nck ham, c.8.. the belief that do,. " hrvc fur. But thir
~~
76
CONNEOIONISM
CHAPTER,
ing thsr thecommon d u r l n mslysisof vcnionr of ~ m t & ~ r rall b u r d on neu with identical archilrrrurer (numhcn of uniu, Ismex.) and just diR~rcnrinitill ~ i g h t lYet, . the d i f f r m m b r r w m biological brains that solve similar p m b lcmr may. ru* be much mare pmfound, invoivin. diU"<"t network .rchitcc. turn, n u m h n of units nc. 50 such rnrlflic tehniqun look unlikely to apply. F d o r and LcPore (19931 nix a rimihr w a y for the more g m m l idea of what Paul Chvrchlrnd 11993) dubbed a "amwrprcc xmntira," viz. a wry of underrtand.ng wmantic r i m i l a r i ~and diffmncn m o t d in p m . * r analpis of r'annectionbt-style r r p m ~ n ~ ~ l i ar pntdr m . Mort Chur
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L S*rnhWnCITI The m a r hmour srpmcnt r g i n r connmionin m d d s of human thought g o s like this: Thought is s y m r t i r : Sa in-d
rrp-nutions
arc ruurtund,
Cannmionirt mod& lack n r v r m d internal reprenrationr:
So mnneaionin mcdclr are not good m d d r of human thought. Uas'icsl adfirid intelligence. bymntran. is r i d to paair r r m c l u d inrcmal rcpmmtationr rind thus to have the n a r d rnourcn to emlain h u m thought Such, r t inrt, ilthe view of F d o r m d Pilyrhyn 11988). who* ro-calld rptcm=ticin/ argument .grim connectionism (qua pyhaloginl mcdd) i s dirplayed abaw. Lc, ur put rom. flah an the bonca. The argument pivot$on the daim that thought is -matic. Thc i d n d yltmuticUIaught is besf crplrind byanaloglvilh syxlrmatir linguisticmmpmncr. A ,peak who b o r n English m d un u y 'the a t lover lohn- %4lusudy hc equalll capable of brming thc smmrc "lohn loves the c r . " This is kuur to bmaiancuaccir toknow itsmrtrsnd howthrrfit tomthrr.Thevmamemm" " " ptcncc (with "lahn" 'loving" ''cat" and rubjm-abjm formations) thvr yield#the cepacity to gcnrrslr a wtiety of unfrn- involving t h m pars. The phenomenon
.
o f systematicilyis thus k d whralvcr wc find a wt o f vpdtiu the1 eppear to hc compmitional nrialions on a single m a w e d rvbnmtc [think of fhe upacity of. cmk, a d vith r rn of basic ingredients, to preparea wide v r r i m o f rrlard p i w m c h n u m d red pcppr, tun. m d md pppr, tunaandchew (yu
descriptionsm d h a t e prfm r t r u c t u n ~ u i t i v c -6-tions (such as turning an aclivr s~ntenrrinto r puriu. on4 withnut first "npacking the I U A M mcoding into its original connitumu. Thcmnclvsion wsthat rompasitionalnruclure, of the kind highlighlrd by Fodoc and Fyyhyn, could bc encoded in a dirtinaivrk mnnmianirt way (the lUAM e n d i n g ) and d i r d y exploited i n that form. Funhndi-ion of the details m d the p r a h h aflictmg thew appmcha u n b.found in Clark 0993, Chapter 6). The p a n t p i n t , houevn, ir j v n t his: ir is an r m d r i u l aucltion whether them can bc a diitinctivrlv connmionm acmunt of cognitive systemmicity. and them arc dmrdy lome aigm of pmgres. I would jun add, howwer, that rhc notion ,hat the root Usuc concrm the uw of highly aructumd inner encoding may itself be something of r diaortion. The dchailtng. land an? t h r is rilllargely unme11is to d i i w c . cannenionikt mrthadr that suppon lhc multiple umbilityof bodin of stored information. Current nctvarkr tend to bcvrry lark specific. Yet human agenu a n ail on !he ~ l m c body of knorlrdg in the w M c c o f many different flpa of projras. This opaciry (which looks doscly mlatcd to. w not ideniol with. 9ptmrtirityar invoked by Fodnr m d W n h v n l is currcndvbcincatudird usinr tcchniavn surh ar 'at" ing," in which the flow of informetion is varied using rubnctwarkr whosr job i s to own and d m channels of internal influence ( y c ,cg., Van Eucn el 1. 1991; lacabs lordan, end B m o , I59Il. Thc othcr m i o r respnrc to the problem of rptcmsticity is to dmnphy rhc enmt and imponanccofcagnitivcs p t t ~ t i r i r y i u c l f . T h ir~rponsciadccply romplimmtsry to the more rmhniral o n e jusr sketched since the technical l.ib look M to buy a d e y r af system=ticity, mullimbility RF.. but may well still 6 11rhon of providing the quimlcnt of an enrcmc vmion of drviul inner symbol maninulrhiiin; , In oiacc of su& c n m c m~nioulabilinithe kind bouehr b r s ramman ccnlnl dslibuc and unilrrysymboiiccaltacc Chapter 2 ) m will p b a b h confront a mom modular sprrm, with no c a m 1 slmbolic r o d r but wirh rn d p a m i d y rrronfigvrabic w b ofimcr c h a ~ e h ainflucnre. f Such system8 must build task flmihilityon topof s mas ofrelativeiy spedtil-purporerdrptrtions. The trouble with this kind of "bag-of-mcb" response is that it is not rlnr how i t can w d UP ~ 10 explain ihc full gamut o f human thought m d rearan. One p s i h l e way to 611 in the gaps is to stre= (Damem. 1991. 1995: Clark 1597. 1598s) the cognition-enhmcingandcognitin-lnnrforming p m m of public language itelf. Th. p r r m r r of. public cdodr in which ml .hunb rilflrn.1 are i n d d widcly rrmmhinahir and highly mmipulahle adds whole new dimrnriorv to hasic hiologirsl cognition. [This is dcmonrtnted in careful cmpiriui dntiil for the rpeCia1 ~a.eofmlthcm~tiu1 kmowldgc in Dchsrnc (19971.1 Pcrhrp,thcn, it is thnr n w (and relatively men,) dimensions that give human thought the appearance of such deep ryramo!iity. W c p s s e s r nor tml-lmyay--that wulptr a d guide our thought in new mp. F d o r and p l p h y n bcliew that our k i c mg-
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n i g k architecturn, * L one we h r e with nonlinyktic rnimds mch s d o p and rabbi~s.itulffakcs thcform ofasymbol.manipulafingcIzuidryncm.Thcir
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C. BOL"zIw
REN.ITY?
The mnrl tellingcriticismr offimt w v e connctlionism wcm tho% th81quntionrd its bi~logicdplsuribility. Such criticisms were lometimes misguacd. to be =re. Any m d r l murrrimpii@inordntoqlain. Butthmspiesofbiologiallybund criticism rrcm to hit the mtk. onewoqconcemr the urrofanificisl torb, a d the choiccaf input md ourput rcpmentations. For although such n-rks l n m d thnr own rolutions to ejvm pmblrm+ what they lamed mnained ha* tainted b y r vnria/of choice made by thc human crprimcntalirr. Such choice included, upxirlly, l c rhoicc of pmblrm domain and rhe choice of mining mnterialr. Ar far a. pmblcm domains wen4 the trouble ws that much of the r k i c n l conrrption of thr natureof the problcmr themselves war mrinrd. Many neworks wrrc devoted lo invnigatin^ What have k n tcrmrd "batizontal micmworl&": $nullslicer of human-level <&nition such rs the capacity to produce the pan tenre of English v.rbr (Rumclhart and McCldland. 1986) or to l n r n simple p m m a n (Elman. 19914. Evcn x h m thctarhlookcd mom h a r t Ic.g.. balanting building blocks on r bnm that piuo~son a movable fulcrum-MrClcllmd. 1989; Plunkm and Sinha, 19921, the rhnice of innur and nutoll# rmracnulinnr wu afim vcm anificial. Thc oumul of the hlock-halmcingprognm. for nrmple.ws not r n l molar action involving ro. bot arms, nor rvrn coding for such action. Rather, i t war jvrl the reia~iucaclivily of W O au,put unita intrrpraed ao ,ha, qua1 artivity on both indirnks in -tion of a nrtc of M m c c m d mru activity on either ~ n iindicate l an u p e t a fion that the k m will owhdmncc in that diredon. The inpuu to thr syslrm,
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Connnionirm pauibla ra sclve c o m p k p m h k without ihrstsndard s p b o l - m m i p u l r t i n g s p prams ruocirted with the aripnd p h ~ i c svl b a l ~ t e hmp r h a i s . To comp l a c t h r r m l u r i o n , howcurr,wr must both .wand a d tune the new p r s p c t i v e . The t u a i n involver ~ the incorporation ofa wider n n g c of features and dynamics. and h punued i n Chaptcrr 5 rhmugh 8. The -$ion involves r e c o p i r i n g ihc pmfaund m l n played b y m e m a 1 m d nonbiological m u r c n in the pmrnotion o f cognitiw sucres. such mourcn include bodily action, innrumcntr and a d hcta, the 1-1 cnvimnrncnt. 2nd m c m r l w h o 1 rtrumwcr. The mull is. virion o f c o p i t i v e a g m q i n u h i c h the inner and the outer play complementary and k p h l i n v n r o v c n mles and i n which the inner computational story is almost m u dirrant horn the dauiul nrian np~orrd inprcviaua rhrptcrs. ~ h W I. -h native virion is b b l o g i d l y p l r w i b i a conceptually a m e i v e , and cornpuntionally economical. But i t b r i n e with i t r nw and faxinating ELI of h u r d l ~ 6m d pmb1sr we rhdl won rcc.
irn.uy
4 3 S ~ s t Wi d O n rannmioninr I.M r C I e l I d . D. h m d b m . m d the PDP Rcrclnh Group (edr). fir. olldfinibutdRmm'~mm'g: Elpbntiom in thr MioolnununolCqnickn (Ombndw. M*: MIT P m 1986. volr. Iand 111 is 11111 the k t infrodunion lo thr r o n n ~ i a n i a-mh p r p m . Uur-himdlytmlmmnX$ include A. U u k , M;nomlnition ICamhridge. M11:MIT P r r r 19891~ndAw&tiwEn~inr$(Omhrids?,M MITPIIrr, 19931. P. M.Chuahlsd'r ~ n g m r o l ~ u u omr n : .%t~!thrsm~~(camhtid~.MA: MIT PICB. 19951is 8 S U ~ ~ ~ I V ~ < = i h l r ~ ( 0 ~ of 0 1 the m n n d a n i r pmdigm. It ,nrlvde ~ b s t a n t udivvuion l a! re~ m n nns x m d en& irich s m c chap", on mom1 and xxial implintions. I. P-~I;~'s Amfiml M,h&IOmbridv. MA: MIT P m , 15951. ha3 vaful rhapars on
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83
rrpn'nnd in S R Gnubrrd ld).Thr A m W lmtr(lipwe a h r (Ombridg. MIT Pr-, 1988). 0" the gunti0nlc0r l~l-lpll.Ym..ti".nd.~m~"mq~~n~N.l.imih"*"mob o!dinm."g gmu 4rrhitrn"rrs uc Ulr n c h n g . h e m F o d a md l r p o m d P.M. Churchland in R. MrOuley led.!. Thr Chvrrhbndc and Their C-tim (Olford. EnsImd: Blsrhrrll. 15%. Chapkr 61 and C rhc n
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ACT^^
PERCEPTION, A N D THE BRAIN
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5.1 Skarhra
1s 18-
* M. Bnl
'Ca (my
,-, , ,
.d~oadw5.3 S
WR d i n p
I t ir limeto m L i t onofthe yidingmotivations k h i n d the compvtationd appmach to undoItmdiog -ition. Th. motivationrr.l,,ialy cr. p r a d i n the 1980r by m ~ Marr. d n major fig. YW in thc h i ~ t o vof artificial intrlligmm. Reflaring an w i c a l naroxirnri& nudies of neuralolgurintion m d n m u n i w o h in vhi
that thcrr rrmaincd a need for
through thr uqurne ofsteps. Thue i h n r l m h of analysis wsc dubbcd the kvel, of rompumtiod thmry lor bcttn. tuk adysir), o f npruolation and a l p nithm, and of implmcnution, i..@vcly. Mcrcly vndcnunding what the n r v d strumurn underlying, ay, virion nrr and how rhc ncumnr fired and mr orga&ad would amount onlv m m aoomchtion d t h c h ~ l e m m u t i o n da &norundmlod~bmnnsoat~for,c.&, tnorforming 2D rctlnal inpuw into a3D model of the viaual xenc. W a r is mkin-d aplmaranly mmcill--ir m under. swding of thr daaih of ihc tuk ( I m l one) and ,he sct of informtion-p-ing step* lihc lnrltxo algorithm) involved. Unlil ihc 1st- 198h mmy cognitive violtirn twk the Marr framomrk rr a liccovto ignorrordownpiayrhc imponanuofundmundingtk biologid bnin. I t is not hard to pc why. Thc brain, it war aped.ir in r o w ma the p h r i d rogior of cognition m d muldfulncs~.But-g t h r t d y nnmdsbautth~ hnin (qua mind-producingrnginr) -4 to turn not on ihcphyrical deailr but on ihe compulatianrl m d information-p-ing rmtegi.8 (level one m d txo) that the bnin I'mmly") implcmrnted. I n sddition,ihcstrteafncumientifir un. drntrnding i n ,how rmrly dnys war xidely p.
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rIgc.
The s m t w bat M u r p m p e d ws to divide rhc uplmaory mk into ththm. F i ,and most important, thocvrs ro k a IIrvcl one) gencnl anal+ of ihc tmli W i g prformcd 1e.g.. i-liring r p r q via mu, identifying ihre-dimcndond OD) objeN via -dimnuion4 (ZD)visual input, doing addition, mning r e a of numben into sequence, what-]. This would inualvc pinning down s p r a k inplt-ourpuf funrtion. and addm$ingthe question of what ~ubtrsluwould n d t o h e o r r i d out in rolving ihc problem Th.n.wi,h Ihc taskthwa li"1ebcttcrundewmi, you could IImlwol go on to d m r i k a vhrmr for nprnmtingthe inputs and ourputs 2nd = upumcr oln.rhontwlsrrps thxt m u l d c a w nut ihr task And finaUy l l ~ ihrrrl, l hanng r J l t o r d wrh a clear hut nlll ahtram undnrllndlna of boih ihc trrk m d r waurn'e of slrm to nmw it out.., mu could addrm the most coneme qualion: ha* do we idually buiLfa dcvicc of rvnning
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6r
Whet ws romoabaur the Man hunwork wr surely this that mmlyundentmding the physiolon ws not -ugh. To grasp ihr origins of mindfulnn. in ihr organiution and a&ty of n r d m n n wc d to u n d m m d h m ihc v l r m ir arpnled rr higher, mom abscncr lmls. and we may n d to arrochte lrpmrofrhnorg.nintion with the wmputstionofcognitivclymlmnt fundona This mint is for~cfull~madc bvthr mmitlvcviendn BDln CannrrU Smilh 119%. . . p. 144 uho d n w a parallelwith t k project of understandingordinary computer m a m r With wpm lo. c.g.. a standard PC running r tax-alculrtion pmgram, ncould quite easily m m all ihc "phpial*ul' quntions (wing sour<< code m d xiring dYylms) rt still lark any real understanding of who, ihc program d a r or men how it wrlu. To rcllly u n h n d how mental activity yieldn mental iutcr, many thcockrr helicvr. m must likmisc undmtnnd something of the m m ~ t r t i m a i n ~ ~ a t i i i i p argrnivliun ~iig d thc bnin. Phpiol+cal
M
CHAPTER 5 / PERCEPTION.ACTION. ANDTHE BRAIN
nudies may conuribus to thk undemanding. But mn a full phyiologiul story would not, in and of iuclf. mcll how bnins w r k qua mind~pmduringengines. The dmgcr, to r r p a h w u that this ohsemion could bc vscd as m cxcux to dowrplay or margindire the imponancc of larking at the biological brain at 011 But al~houghit is true that s compuatioml undmmding, when we haw it, ir i n principle i n d c p d m t of the details of sny specific implmcntation in hard-rc (or welwm), the p m i m of d ~ m v n f n 8 I hml-t ~ computationaldcruiplion Inp i a l l y for biologir~ls y t m r l s qullc definitely nor. Onc liy fmor here is wlution. Biological bninr are the produn of biolqiul nolution and u rurh often fail to fundion in thc wy we (as human dnignerr) might crpcd? ihc abnnrl 'dnigm m n d I r e Dmnat. 1987. i n d Chapter 3) that w arc invited to hkc at Mnrr's I n d s one nnd h*,is hang+ to b r h our intuiuive idear about what lhccognitivrtsks rcaliysr. (irvirion redly sboutrhicring a mapping fmm 2D input onto a 3D world rnodrl?We will hccr find caure for doubt) and to our rclrtivcly prriudiwd xnw of the s p a of pouiblc deigns Biological cualution, by conmrt. is both conrtraincd and l i b c n t d in wars wr arc not. It is mnnraindto build itssolutions incrcment=llyon fopaf simpler but succ d l mccrlnl lorms The human lung, to giveone eumple, is built via s pmcnr of 'tinkering' (brob. 1977) xifh the swim bladder of ihc fish. The human cnginrrr might derign a M a lung fmm match. Ihr tinkerer, by cantran. mun take sn nisting d o i r r and subtly adapt it t o r n w role. Fmm the engineer's ahisroriral prrsprtivc. the tinkerer's soiulion may look biwrc. L i k e , the p m c e ~ i q rtnrcgier used by biological brain9 may rurpriw the computcr -ti& For such strategis hare rhrmrclvcs bccn evolved v h a proof inrrcmmral, piwemnl. tinkering with older oolutionr. More pmitively, biological m l u t i o e ilibrmld by k i n g able to di-r rfficient but "mrsy" or unobviovs ralutionr that may. for cumplc, exploit cnvimnmensl inenrriansand fdbacklmpsrocomplrxthat theywouldquicWy brf& a h u m n cnginm. Natural solvtions Car w will later -1 u n crploil ju* a b u t any mirtun of nrunl, bodily, end olrimnmcntal msou- along with their compi- looping m d often nonlinnr intcraaion~.Biologicalevolution ir rhvrrblc to c x p l o ~a wy different solution rpcc (wid- in rome dimensions, narrower in othcrr) than that which beckons to ranwious human rcrson. R m n t w r k in copitivc newowicnu emphasiza ih~dinmcc-xpanting biologiul m d ' m e n d pmblem oolutionr. and display an incrnringawrencu of fhc impomnt intrrpnnntion-in biologiul sptptrm-f pcrccption, thought, and mion. romc brief should hrlp fir the flavor. A s s prnllr mtv polnr. ronrndrr some men! work on the n e u d ~ o n t mo' l monkcy f i n p mollonr Tnd8tnonal nrdom deptlted the mulkc* s fingm rr 8". dtndually contml'd by ne~ihbo.lng ga.~rpr 1.y.~aall~ clu\tcad r~rucuans A,.
mudinglo thk stov. the nrvrunl Inn Motor Arc. I.or h l l l r r e o r p l u d as 'wmatotopr m a d in whnrh 2 dedroced nmrd suhrrgian governed r x h indwidu J dimr. sn~nud m .o.ttrl m u e n r e , #u%t I*c the finem on " .*.th thc subraanr " n c h hhmd. Thir is a tidy, -ily cronccpfullizcdrolution to thc problem of finger contml. But i t k the cnginccc'a mlution, not (it now -) t b t mf Naturr. Schiebrr and Hibbard (1993) haw h o r n that individual liner movements srr srrompsnied by artivityrpmd pretty well throughout thr M I hand arn, and that prrriu. single-diet mowmenu rctluUyqnirc more actinv tham =me multidiet whole hand rctioru (such ugrasping m objxr). Such mu18 are inconsirfrnt wifh fhc hypothesis ofdigit-apcific local ncurorul goup Fmm a mom cvolurionry pmpcaivr, howtvcr, the nrionrlc is obviou. Schicbrr (15% p. 141) conimures thc buic rncntral nrcd wr for wholr hmd-gnrping motions luwd to m b b r a n h a to win=. ". to acouirc hits.nc.1. a d that thc moat hmdamrnul neural adaptations nrr thus gcnrcd to aUow simple commands to orploit natunlly x l ~ l inbuilt d synergin'of mvpclc md rndon ra u to yidd such cb ordsnltcd motions. The 'mmplc." coordinated nr. i s lhvr omlufionarily buic and ".".aly aimpl~r.The "rimplc" task of contmlling,c.~..n individualdigit reprmnu the harder pmblrm and rrquiru m r c neural miviry,viz. the uu of r a m motor cortex ncurons to hhibrr thc nstunlly mrdinwtcd eaintyofthc other dig. it*. P r m x anll<-dlyl mo\cmmtr lhvl requm thc ncunl control r).nrm l o ttn. kcr w l h wholc.hrnd command', mndthlng the hr'ir coord8nlcd dynamm lof
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m r r h ~ n t o l l v I ~ n ~ c d t r n d o n r.n"~ . I n c r r r d t o f h c m o r r ~ o m m o n l r h o l e - h a n d l ~ * c k ~ Conridcr nen a c a x of perceptual adaptation. The human prrccplual ryrtm -0. we h o w ( g i m time and mining). adapt in quite powerful way to distorted
pri,ia".rhihed inpa.. For cumpl.. subims can l n m how lo
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s u y o l w r h a l x n r n m 4 xr W h h (19111. 'I" ,h"ux.n , h . u r . n * p ~ n d r h . " ~m ~ h r n o r n r n ~ . 'lor.
M
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CHAFER 5
I
PFRCEPTION. ACTION. AND WE BRAIN
mlving the urc of the nondominant hand to throw, or to an undmrm w i r n t of the unul w m m throw ln)itnd, adaptation ImMtobc -rind toaquirc.pccificmmbinntion afgozernglcind thrawingmgl.: the a n c d inovmrm,dominant-hand throwing. Somethingof the neunl mechmiism~ ofsurh idaptdon ir now undarood6 The p m l 1-n, h o r n , mnrerm thr amNR ofthc pcrcrp~inwnion~ y . r r m itdt For it inmasingly a m r s that the simple image of r ~ n m purpmr l pcrreprurl syslrm delivering input l o r dirrinn a d fully indcpndcnt action r y t m is biologiully dirtonire. I n m d , p r q t u a l and action m m s work togcthcs in the context of *mdfi
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I.Dailyagmtmvimmcnr inl~"doU5 w m not to d@on m d u u ddcailcd inner m d d r of the W I 3D xene.
the comruttion
2. Law-lmlprcrption may -all" motor mutins that y k k l l d b m n p r r r p t d in-
put m d henu improw inform.tion
pi&-up.
3. R ~ l - w o d d d o n s m y ~ m ~ i m a p l a y , " i m p I t . " t ralcin Lhrmmp"tati.tian.l process itrclf. I . The intcrnal rep-tation of woddly mt.m d rtrvcturn m y bc krr like a w i v e data armrun or decription md more l i i r direct mip for ution.
QUE
VISUALSYSTEM: THESUBWAY MAP
~. w 5.1). The comming pathmys P b t h upward end %wn& (r.&. h m V l toV2 snd b c k =gin)m d aid, to side (bdwrns u b a m in V l t r. eg., Fdlemln rod V m Eavn (1991). 1nnidu.l ah e l 'higherm I*& of pmeniog, rvch u V 4 (v"ur1 area 4). do. it is rmr, e m to d i z in the recognition of rpdfic gmmctrictri forms. But l k y d ala rrspond, in some dto many 0Ul.r ldmuli The a r k tbw hurtion not u eimpk future A n but u 6lmr mmd dong r whole ran- o f nimulur di. rnmianr (wr V.n Fsm m d GdlmI. 1990. The m a infomtioadly dg-
F
n i b t k t 3 t h u &en conma thcpncmsofa&n(ofvholepopul~tiona of -dl m n d fin-a imqe much more in ILu with the connectionist &on of Q u p r 4 than the spbolic anc of Chapters 1 and 2. To add furthncnmplimion.thr rcrporuaofmchccbnowlmkto bcmdlfirbkboth by "&tion m d by dddliL of 1 4 td-s+fK contm (Knierirn and van
. . . . -. ..;,">," . ,.. PPCn. 1992). 1. hnt.ck-pm& (cadcmnhl) m@., thr marlul, m m n m k fonuda a c ~ il,l h m aremore~ r h m I pding horn d q (nsidc the bnin o u r w d tmardthe -my p i p h e n o than vlce v'nm (though much of the ~ l n m i v i t yis rrcip~ool.ScrVao md Andacn (1990)*dOnmNmd a & (1994,p.a). v w d p r o a n i n g m W inwlvca a wide vuiq ghly. ifadl b e d a P i k d r (PIcrpcbn m cognition) h
dh
PerCCplion. M i o n . and thr Brain
9'
Evidma for pmporition 1 comn from s w r i n of experiments in which sub. jCdr w t r h image on a computer rcrrm. m t h c s u b j e ' ~eyer ucudcrmund the wem (tocu~ingfin, on one rra, ihm enather) c h m p are medc to the dirplay. The changs~,rremade during !he virlul scud- 11is sn amazing fad t h r , for the
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wlmrturl v u l smga the trd e n w n 'dl I h ~ vrd r he LCNI, plw rrml ronnavl.[urn77 olanulo-r, m n a pnmul.1 M'O. Ur L R d hl-mp.l rompnll na.2a r r r m n n d h Iw h n t . ~ nm of& I h n c -, d m o m t d mb. rm& amnn IF- Ml-n snd V m Eum
....
. " " ~-~ ~- ~ ~ ~ - ~ ~ - ..... .... .. r tree bv a shrub. or the sddihn of a ar. deletion of n har. and w on. Whv do -~ N C ~ gmu altmtions m m i n undcrmd?A compelling h m h n i r is th.r the visual vtm is nor even ancmpling to build n rich, dcrai1.d modd of the c u m t wrnr but i*i n n e d gnmd to wing fqucnr ucudes lo mcrierc information ru and whm it ir n d e d far wmc specific pmblm-solving pu-. This fits n i d y with Yarblu' c h i c (1967) finding that the pattern o f such sacadcs -ria (nm with identid % m a ) .ccording m the type 01 11&1hc snb+$ hm been sn ( c . ~ . to give ihc r p of thc p p l c in r picture or to guar the adiviv they haw been mgagd in, nc.). According to both Chvrchhnd ct d. (1594) ~ n Bd d d (15911. wc arc prone lo the illurion t h a m conscantly command r "ch inn" rcpmentrtion oflhc Nrrolt nrud ~ ~ arc to ocrfocrfm i thcx h ~ ucclder. mtdwing information an and when rquirrd. (hn andagi": r modern Ifox m v p r n c n t the illusion of having a masiv. mount ofgmds ttmkrd on the pmmisrr, b m u t r i t .Iwayr has A r t you went when you want it. But modem <~mpufc~-~rdcring sptcms mn automatiully count off rsln and .quisition o m items ro lhrt rhc nwesnry p d r am anihbie ivrl whcn n c d d and barely a ma. mcnt before. This jut-in-time 0rdc.g sptcm a*n r w i v e saving of on-rile norage while tailoring supply dimculy to customer drmmd.) Contrmponry rcsclrch in mbonio ( r e Chapter 61 s n i k itself 01th- ume rronomis. Oncoflhcpionrrrrof'nwmbotin" RodnqBraalu(~.e&.B m o b m1)
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CHAPTER 5 I
9'
PERCEPTION. ACTION. AND THE BRllN
the trbkrurfacedradahad O n w r a n ir mwuntcnd, i t is grupd..ndmlImd m d thc m b n mows on. Notiw, thcn, that H c ~ d h o u f using m y convcntionrl planning wchniqun m d wiuhaur rrnlingand ~pdating m y detailed inner model of thcenvimnmcnt. Hnbm'r world ir c o m p d of undiRIrrntialed obrtarlrr and rough table-like and can-like outline. within this woild the robot alto exploits ia awn bodily action$ (mtaring the lorso to c m m the cm in iu field of vim1 soar 10 gnrtly simplie the c o m p u ~ t i o nprahlrms ~l i n w l v d in m l u aIb mching for the can. Hcrbcrt is thus a rimplc m p l c of both a *tern t h n a v d r using minimal qr-mrionrl neaur
of this m e bmsd n m w , vir thc u u of a h n d o f perupruomotor loop whmc role u to nukt the molt of .n
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ably why, u Churchlandn.1. (1594, p. 511 ohacnc, hcad babbingbehavior is frrquently wm in r n i m l e 'a vinul W r m &at inrcgnb a r m s s . 4 glimpcl to ntimatc depth h u compuutional vvinga a m one t h L ttics to almlatc d r p h fmm a rhglc maphot" And $0 ro pmporition (4): that the n c d mpmnta6an of warlay m a maybe Iruh a p-rc d m lrmclw a d more lk r mip. for mion. Thedtiving force, on- a m . ir compvUtionsl conomy. I f the g d of p ~ r v p t i o n md rnsan is m guide d o n (and i t hudy iS nolutionvy rpcakhg), i t will oficn be rimplcrto r e p n m t the world in vryr rather d o d y sued to thckindr of anions wr m n t to pcrfonn. To I& r simple uunplc. an animal that uur is \*ual inputsto y i d r a spcific Lind ofrrachingbehrvioc lro as to acquimnnd ingest fmd) nrcd not form an obi--cmnterrd rcprcrenrrtionofihr sumundinglpace. Intmd. a Wematir m c u i d umaformrrian lachiwd by a point-,*point mapping bewrm rwo intrrnd map) may lmnrfom the visual inputs d i m l y into a mip for m B i q o u t m d phbingthc food. I n such r sct-up, thc rnimd d o a not nnd to do sddiliod wmputatbnd work on m # A n - n c u h i inncr model w, as to p l m 1 marhingmjcctory The p r e p l u l l w i n g is imead mcrkcd, at ansugr, in r wry dictated by the pmicuhr wr to which UIe visual input is ddi.
<.,.a
IO
I n a related win, MPja MaUric o f the MIT Anifitid intdlgmce W n m r y has drvelo@ a nrurobiologidly inqimd d e l of haw rats navigate their rnvimnmmm. Thir model rrplaitr the kind of 1a)r.redarchitmure" alw, uud in t k mhot Hcrben. Of mmt immedirlc interest, howmr, is ihc wry the mbot lam about iu surmunding. Ar it move amund rimplc m a , i t detrcf. ladmark that UI wgi~tmedl e e F i y r n 5.3, 5.4, and 5.5) sr a cornhimtion of umory inpvt and m m n t motton. A narrowmnidor thus rrgisrmu r mmbinrtion of f o r w r d morion m d rhnn lhlrml disnncc reading fmm mnsr rcnrors. h t c r , i f the mbot ir required to find its wry bark tor. -embed location, i t r n t i m r " m interlinked xt of rurh camhind wnsoy m d motor m d i n p The rtored "map" of the rnvimnmmt ir thus immediarciy fit to a n u r r e p for mion, since the motor ripals rrr pn d @he nored spatial howledgc. The relation bm*een two loutiont ir d i m l y d e d as the u t of motor signals that moved the mbat tom one to rhc other. Thc inner map ir thus irwlfthe r c d p for rhc necessary motor Mionr. By conmn. a more clauiul approach x o d d fin, generate a more ohMtivr map, which would !hen need to be m n d o w t o phn the mute.
CMAPTER 5 I
PERCEPTION. ACTION, AND THE BMIN
1
P c r ~ L i o nM . i o n . and the Bmin
As n brt nod i o fh.1 -c dirrrtion.cMlddn the -ling cuc o f t o - d d mkmr m r o m (oi Pellegrino ct d.. 1592). Thne uc luumnr, in m o d q m n a l premotor mna. that are s&n nirntcd. wntm d-drdr~. md h p l i a n d io bah wlf-initiated r r t i v i t y a d passim prcrption, Thsr nruran, rn aivl bath whm the m o d q obmn a r+c action (such rt smmnr w i n g 8 f d i t c m ) udwhmthcmonk~pnjormrth~rsme kid o f a d o n (in thi, u w . the grvping of r food itdm Ri~i.lolanict d., 1996). Thc impliarion, auording to the pr~holopjrtand ncurauientiw Marc Ieennerod. rr that -the x t i o n . . . to k iniliared ir ntond in fmnr d
-.
I
Naughrm md Nadd. 1990) r m p l i f i s the anractionr of what I all 'anionoricntd rrprcwntalioni" (Clark. 1597, p. 49): rcpcpcvnrstionr that demnk ihc world b~ d v i d n g it in tcmr of pauible aaionr."Thir image fiu niccly with xvtnlolthe rcrulu rrportdnrlicr, inrludingthcrmrkon monkqfingcrronlrol and the molor loop iprc16. s o l 'pcr
A
6
CHAFTER 5
96
I
P r R c r ~ n oA ~ .~ O NAND . THE BRAIN
Canrider o n e rmln Mm'r th-rndinindon
a m n g usk.dprithm. a d implcmmationWehr~1-hmdmi4~fbodjl~mcrhm~(~~~of&nr. LIC.) and embodied adonUking(moving,vi~urlm~dnnr) wr n d i d y i n n r -
form the shape o f the mmpuntiond problem ficrd a rral-uorld agent. This fict alone nuts o m u r c on the onnical d u e of the thm-1-1 rrhcmn. The trsk of v i ~ u rprwnsing l m y have pmheoretidy s e m d to q u i r e m algorithm for msppingputiwly r& 2D information onto a 3D inner modd of the a m n t
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Irtion. and th. enin
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The inuc of timing, d, in fact, l m m rather kg. in ?ame of our l a t o disrwsions (YC Chapln 7). For timing conridmationsarc a h l u t c l ~ r r u c i dto mam uprm of neural functioning, including lenaaMlotor mnrml and m n ' ~ i v c " information pmessin& Yet dcllila of red riming nnd dynamicr uc inrvinbly wnrhsdaut in p~reslgorimmicdcwriptionssince thncs~ipeeih.onfyihrinput a d ovfput rcpmmtstions and the wqurncr ofmn~formationrthat nxdialn ktwccn them. Crucial erplanaror). work thus rcrminr to be done r v m vhrn a full dgorithmk undrsnnding ir in place. O n e r g i n , the nolion that undmmding naru n l m i t i o n is simply undemandingthc alptithms that the b n i n happens to implmrnt h nlld , . ,ni qu~ian. Finally, m a l l ,he diuur.ion ofmnn~lioniam fmm Chapter I . one halureof thov modelams theapparent ralbpvafthe datrlalprithm di~inctionitwlf The mnnmion r i g h n . in such models rct u both bowlcdgc r t o x a d knowledge mmipulorion algorithm. I f ml ncunl campuurion is i n W myhing l i cannmionin computation, the r m d u d notion of an slgotiuhm ar s mipe for acting indrpndenf daa wt .Isa s r c m sui* imppliublr. on Ovcrrll. then, we mny q r c with Churddand and ScjnowaU (15% p. 2491 ht'Marr'r thrre kwh ofawl+md the brain's lmlroforgonuarim do nn rp. pcerto m& in a voymeful or satisfyingmanner: 1x1pmcuiar, implmenmion Imlb o w l d g c may b.c%Srnti.l for ""dentanding what the hcnrural Sy3t.m conhonu. W r may alw, need to rmognirc a mulriplicity of mughly algotithmk I w r l h " and (perhap) m *k +of undennndingihar arc nor cuilyclrrwd u algorithmic at all.
en.. B a rcflrnion on the TOIC of metion a d a d o n and on our rpcrifir k h v lord nrrds at m y girm moment rugs510, we mw, a much more minimdir p i c t u r c a n r in whkh r mobile, embodied w t m mctivehwb the kinds of limited information m d nturlFun than will msble it to hd6U r sprcific m n m t pal. and no more. Our nations of whdr top-lml ta* n d to bc performed. m d of are thus d w l y informed by what kinds of algorithm irr adrgwte to perform i~ reflection on dctailr of bodily implcmcntation, m m n t needs, and aaion-taking patmtid. Such obsrm60na" do not d i d y u n d m i n e h e ~ d g o r i t h m l i m p k m e n ntion dirtindon itself. But they do 1 the parsibility of an upward u r n d r of influme in which m n iwhting the right tuk drpcndr on .nappreciationof dc~ a k o l b o d ynnd imphntrtion. Morr n d d y d l , r dour confmnutinr with n a t d .ynemr orb mmc doubt an the biologial qpliubility of fhr three-way dwmc!wn 8twll. The root olthe p m b l m hcrcrlwuu 'un'mu lhc propcr *.).lo map the thrrr arulyii level' ~ ~ ~ W d p . ~ ~ r ~ ~ Y Oh O~ actud ~U ~ J~ ~. d~ s~ ~ ~ ~ ~ l ~ ~ ~ ~ ~ ~ ~ c ~ c ~ ~ ) ~ ~ ) 8. COMPUTATION AND IMPLEMENTATION o!nranl ohun8ulnon. Thuscnnnnhland 2nd (r(r(r(r(rL .1%. .. ~249,obrcrvcthal " h e w are many l m l r of n m n l orpniution, including "the biwhchcmiul ..the Pmcrrding fmm the wardward m i d in the prNims -ion. mnridn nmt the usk mmbnnc, theringle rdl, and the orcuit, and pcrhrps bnln sub~ytrmr,brun of distinguishing "camputrtionrl" fmm 'implemmtrtiond" f n N m in thc fint -tens b n i n m a p m d the whole ccnlnl n m o w rptm.' Whkh of t h e wiolare. PO. moat human-dnimed " mmoutrrsvrl~mrthisdistinrtion b c w t o d n w olu I-& of organbation i s the Inel of implrmmtation?Obviously, the a m But Ihk pmbrhly r c h rhe m h v e of cauciou. dl$+ procagin which the dcpndr on exactly what function or urk wc are studying. One rnult of thi mulmginrrr or programmer finr contrives of a problem solution in rof an rbtipliciv of porsiblr trrgera, however, b th*r whm ban dgotithmidly intrrcsring snact rqma of simple nepr and t h m implmcntr ihc wqucnce by r u a i l r i n g dr.rl relatorr loone trrk may nllk 'mnr ~mpionrotfaloon Jcld.1" rclal#rclu an. a h nrpwith a dbrinct snd m ~ h n n i n i ~ t r s c l r b l c a p r i oThis n . rtntglrypwhcr To undentmd ;a
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CHAPTER 5
1 PERCEPTION, ACTION, AND THE BW1N
pempio". Adon. a d the Brain
design to mnfonn to the priMiplcof n n t fonctio~uldcmmpmition. Imrc~d.rrolutionavrnrch (by pmxnar such as random w i d o n m d diffcr.nti.1 vlmian) un un-r pmblm solulionr that dcpnd cmcirlly on complex iarraaioru km e n multipucirruiu. This is r corner of designspace ~uriourlyopaque to m n x i o u human ~ n r o n . which ir far m d n v r v mnrt mmfn.tshl. with simnlc lin.
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paw of 2 bit *in@ to farm a nrw am1 and random muWion Iflippins romevalues in. hit syin& for nrmplc). Each n w grnmtion i s a m tat& agriinn thc fitnus hnmon. and over h u o d d ofchaosndr afgrnartiana pafonnrc loRml dramdidly improves, lo the point d r r c highly evolved bit .dv. the ~ m b k m in mburt and &mt mys. Cknuic algorithm haw k n r u c c ~ h r l l yuud for r varin). of praniul i n d thmrnxd pwpmrr including thr woiution of good wight assignmenu for ~~
a problcm rolution war found char depended on !he slightly different inputoutpus timr delaysof componmts. mew ddp l fixed. but rcrandamiution at the end of thc r w l u t i o n . ~=arch now dntmycd SuCreJsfd pdormmcc,rhowingrhar rhccircuitr hrd.uncrprcrrdiy,iamcraupioil chore r p i f i c (and randomly ch-1 delays ar pen of the problmwlving configurnlion. The authors comment that, in gmml:
GENETIC ALGORITHMS
GmnaLdprithmr (GAS)wm iarodwdby lohnH& (ins)u ardmpvationd rsrion of lmwthing akin a)bdagid N d u t i m l h e id- wu 10 Wrc +papulntionofcomputPtionnl'chmmmomn"ditatrio@ lo aubjm them t o r @me of trirl, variation, &rtm ramfion, and reprodurtiaa The bit atring. would cn~odc.or a Inn k apaMe of raroding. posihlc solutions to lome pmpdfied problem. A fitncu h c t i o n (a maa r c of howw~Ucmh hit k rble to pdnm th~h k ) idmti6et which mcmbcrr d r wid inilirl population pdornbcrt. 'Ih- form t ka d ing sock" fotthe next gmrnnluon, mated by procma of(miring
.
There err. h o m r , ways around this a p p u n mismatch. Computationrlir lately exploit so-ulld pnnic algarirhmrL~ (rrc B ~ 5.1) X that mughly thr prof crolutionary r n r r h and aUow the discorcry of efficie~thnt romnimes Grange and highly interactive adaptive rtnregia m d pmblcm rolutionr. A menr menrion of such rpprmchn usn a variant" kind of grnetir algorithm to search for "0"kinds of hnrdwrrderign that rr. hcrd from chr "rimpiifyhg
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production line), of control v c h i t m v m for robotic devics, m d (wr r u t ) of cffiornt iprial-purpou silkon chip. Far the dasi' intmduction. M Holland (1975). Far some uwr~fcimdlyguide,= HoIlrnd (1992). F r d l h
** otian.l!y
it w k W that all of the d a i l d p h ~ i ofth. a hardrrm win k hmught to k a r on chr pmhlm st hm& time d e h p peruili npciunrcs. <mu-uk me.. suhilivmnar~intiandother lolrlevd chanclcrutics might a11 be uud in gcnenting thr ndnd hrhanor IThompron n 11. 1996. p. 21) Mom rmrntly. thesame group h.r u r d hardwm cvolurion to dmlop s chip thsr disringuitha iw, lone (1 and 10 Hz). Convmrion~lrolurionr rgrin rely
heavily on a global clock thrt synchronizes the action of mmy lagk b l a b . The wolud chip dirpcnwr with thc d a k and maker full use of the low-kwl p r o w tie of the phystoi dcvicvicvi. Once nyin, the result i s m amazingly ~ffirimrdnign ghat m s 21 logic black mmprred so many hundreds in the conventional chip. ma this work lrnd work in r o a l l d ncuromomhic VLSI"1 show is that low-kvrl physicalp m ~ i a of , the Lind esaistrd m l h srrual physical implcmenation rather than abstract mmpulatiand deign6 ran k rmpred (by m t u d or nnifitid nolution) into d o i n x v q substantial pmblcm-solvine work. Whm r fully np~oit, N C ~low-lrvcl phpiral fcatum. it upab~;of m~ving ~ i f i pmblcmr c with an rffirimcy dm to that dcicrmind by chc limits of physio i f v l f i t "mains r vo;d qucslion whelhn wrrhnndd n y in r t r h urrr #ha#the ryrtrm is wiving the problem by non-computational mnnr or whether we should
CHAPl€R I
>W
/
WRCEmON, ACTION. ANDTHE BMIN
sly, ralhcr, that nrtvrc ir ah* lo put these un-dy subtle and la-1-1 pmp. enin to " .ood mmautstiod uu IIm r clear that mtrrtmg o u r v l m to ihlevd of fimdnu kinds of nthmr 5pnlicstoon 0s a pmr aralcgr ifwe hope to undmund fhc wv boolo@ ul b r a curd* mtcll,tmt rooon lnrrad we m u~ l ~oar 2nd runsunr anm = rlnv -~~-~~ , lion tothe nrturemd pmpcninaf n a r d circuits m d to rhcmmplainter=nion. among bnin, body, and environment. Thcsmfegof h i n g a l t r n t i o n on r kind of disembodid"pumrahr~"levol,flwtinghighabovcthcmcrsy mamirl maim. works well r h m m ronhont mmpuntional systems of our o m d n i p . But it works h c a u u of the simplificrtionr, rigimmtarionr, m d n u t drcompsitiom *r snoLirlly ompovon t h r r r o m n r oamtn roar lo m&r1 rrrarblctofhr p r a n . ofronv,nu ,in ohr tir., ~ ~ ~ . ~ ~ mmcatr. . t ~ unerpmd, ~ d ~ ~ ~ i h ~ ohm itunn,ndv cffinrnt orodu
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C M T E W A L FMGMWIATION AND CWRDWATED ACTION
Thoe ir lomcthing deeply h.gnmmy a b u t the vidon of nrunl architmure m u t 4 earlier. The imageof multiple p-ingauermr m d of ?=id-purction.oticnr4 q r r m l a t i o n r mmhineto yield a dininniw virion af the nrmnl moU of intrlli.m, beh*\i.r in which cffii~imt mm7nSI dcamdr on the areence of what the w i t i w ncurovicnrireV.S. Ramachmdnnullr r "bag of tricks." The idea, then, ir that inrelligm~edoes nor dcpmd on rhc mndatian of incoming information into some unitlry inn" Eadc that h rhm o m t d on by general purpmc logical inference (the c h i d i m a r pumud in r u n x h p-ms euch u ,he SOAR pmj=t--ut Chrplrr 2). Inrtud, nconfront a mixed bag of dariwly sptialLpurpow cncoding and lrahgrms who= o v d effect ir to suppan the p.nia1.r , 7 4 3 01. crn.,n kind of <,"lure arvp,ing. sprrik
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pasing, in whkh thrrc is no rich trade in masage, hut rather an ~uncrreuadc in rignrlr that either mcounge or inhibit t h activity of other cornponenu. [in the mbotia ~ i t . . ~ t ~this ~ , \ision i. inthr idu rubsumption.r&i-e ( B m o k 19911-Bar 5.4.1 Annctivc u the simple sipdlngmodcl L, m o w m m p l a ~ r v i o n w i l l r m l y rcguirc addiliod kinds of internal mordinrtion. Contompnry nolmuientific th&y dirplryr a nrirry of propos& that fall midway slang @he w r m m of inrm.1 rommuniulivr camplrriry. Thw Van k n n =I (1994) . posit nmrd e p t ing" mrchanirmr whore task is lo quba ihr f l m a f information bmm coninl ~. who- Uamrlio and Uamasio 119911 w i t a ~cnn of "convcncnct rona": a m in which multiple frrdhad m d f d o r v s r d connmianr ronvrry m d that a n ir switching ports u, i r to bring about the rimdtrnmus saiviry of thr multiplc hnin .rear implicalcd in m a i n tasks. In bath thrv caar, thee ir no wnw in which rhe inner ronuol system (the wing neurons or rhc mnvcrgU)M)has a<(es to all the information flowing through the $ ~ r r mThne . am not 0:~~tivecontroUerr privy to all the informstion in ihc sptem, so m u d u rimplc mitching rgmtr, oping md rloring channrls of influen<. bcnrc" a wide varic* of inn- pmeuon and componm~.One might r l w mnrider the wr of wcalled dirsipatin cffcdr. The i d n hem 1- Brooks. 1994; Husbands u rl.. 1998) ia to cmloit the u o l r i ~ ~aorelead f s u h n c c 1c.r. ". r chemical ncuramodulrorl to iu&t thc pmnsing pmmc of r large chunk of the op;rcm. Such rubran<; would bc m l d , have Ihdr e l i m s . m d then dissipate, rrmrninr the mtcm to normal. The r a o d h t d bchh.*ior of multiplc inncr components a n 1Lo romnimcs k * c h i d not via the wr of inner sipds or diffuw chrmicd influcncn but by
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p u &kc, iuoaanrUy q i n k a t to r simple w b k mb4 clpablc af Ff d g j u t om Urlr 'Tlr mbol H a k n ( d l in the tur) rompamlriol*ihof such simolcrdr*ircs: ramr for obsode ewidulu, romcfor cxphring am. for tabla -itian,rtc. Obriowly,thcrcodsto krornc ldnd of raodiwion brtwrro the hyerr. T h i ~ ia didnor by the interml ~rsnrminionof mmpla m s q e but by ~w uuumirrion of amplr s i p & that l u n om de*icc on or off* mother.rhim8 remhnatc (c.g.. the t d r t s r l i m of whed motion initi.tn gnrping, ihc ddndon of nn o h de inhibhs f a m r d motion, rtc.1.
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CHAPTER 5 1 PERCEPTION, ACTION, AND THE BRAIN
101
B c action of the mcmd cnvimnmrnt irrcll. M v t h of Hcrbcrt'r cwrdinared ncrivity (wc tm and Box 5.4) depends on the flow of acrual m"ronmcnta1 trigger..
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ROBOTS AND ARTIFICIAL LIFE
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mindcn i n i d ~lmtions, t or when w lay out the pa* of a model plmc in the mrmt order for asrmblyl. This devolution of mntml m the lml cmimnmrnt L r toppic to which w shall mum. In mm, i t remains v n r l n r h a w b o t r o p r r s mardinrted hhrvior from* "bag of s i c k - rrylc of mgnitivc o w n i m i o n . But p r n m i n g the p i n s m d adnntsgn that rvch a r+ of org8nhtion orerr precludes & uuu of a central executive md 2 hr."yd"ty m-pr palrlngcode In,md..ppmpn.,c<mrd n.,mn mualamrh m r m r q r horn the Lu of r,mp1
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nr
C bmnrn C pmha~oslandnrvmvinrr s ~ ~ . I ~ ' AD. . ' M ~ I ~MW. G~~.IC. ~ ~ virual Brnin in Artson (Orlord. Endand Oxford Uniwnin P m r lWS1 lor a dcrr but pm-arirc story .bout nsion and action. The rms* ani1r by 1.I*rm m d T. Gina, 'Nan1 nrrhl"rcrn. ,"burui"@ Ih. ammtion alhumln a!51, 172-178, IW,idwr uvfvl moumr For a philaopbinlly, I-omput.tian.uy, rnd n e u m w c n t i r r l ~ i n f o m d d i w u ~ b "of I h q u a i o m a b ~ u t I ~ l ~ ~ a , m l y n r ~ n d ~ l ~ n aChumhbcdmdT. tim~P.5, I.~jnmr!+ Thr CamplallannlBmzn (Ornbndge, M* MIT P x r . 19921.8 den% but 1 ( ( ~ i b l lml. e m n , of ro",rmpon~compvlltinnll neumwi.ne with nprially vwful d,xu.non.of ih. i s v n conerning l m l r of a n d p i and lrwlr of dcxtiplion, m d PS.Churrhlmd, NN. roDhilom~hviClmbrider, MA M K P-. 19861. r h k h r l w mntlinr r wlu1 and 8-iblc prima on bsrir neumuimce and neurmnaomy. Thr vo,kon m , m , , n 632" . " d r h . n ~ - b l m d n s l " n I ~ h d d m in ~ P. S humhImd. V. 5. R.m.rh.ndrm, md T.% .n ;ow i;l "A cntiq". a1 p"w vi.an: I"C. K& and T. oms (dr.1. ~nrp-srok~ m r o n ammnn ~ ofrhr ~rclini ~ m b r i d g rMA: . MK 1994. pp. 23-1. En also ihc rcriw lrlirlcr by D. Simonr m d D. E n . "Chmgt blindws.' rmd, iv cqnitivt*;mnm. 1. 261.267. 1997;and D.nabrd. "hima hion.' Atific?.dlnfrlllmi~ IR, 5 7 6 6 , 1991.Thc lrlrrr is ivrt ahou?the p d c r l inlmdudion Io
~~~~
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~~
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nsntin~thrmrrinph~laoph~,romtu.,mdnrumrrirn~,rrr~.~l~r~enaThm~umng
.
Bnln Body ond World Tqdho Akin (Clrnbridgc. M k MIT h r 19971. And finmllr ihr nnuur c u r s is, Ikd
..l*ing
r UL .nd Wnd
6.3
su-
Rnaw
6.1 Sketches n to encounter our firn aampla o f work in mboti-work that fills bmldl" wilhi B e field that har come lo bc known er rnificial life. Thir work is c h m c m i r d by three dirtinct, but intmclated t h e m :
In Chapter 5, m b
I.An int-t in mmplcte bet l o w - I m l synemr (whols, relatidy autonomous anifisid organisms lhat m w i mu and a d in miistic mnvironmmrs]. 2. Recognition of the m m p l n mntribvtionr of body. action, and cnvimnmmal
3. S w i l l anontion to kuer mnvrningemngmce and mllmive cfleas. Inthir r h e h , 1inuoduc, thnc tapiu wing om m n c m rumpla:: crkkct phonatnrir m d termite n s t buildin& The i n t m r t in complctc but l o w - l m l s p m r is m a n hmowly nlurmted by uodney ~ r n o l uwork ' on mobile mboa (maboa). and by robots rurh a, ~ c h whom we already met i n Chapt~l5.BUI the idea of building such rraturn gon back at l u r t 10Ihr n r l y 1950s when W. Grey Wdtrr created a pair of cybrrnctic tunlcr named Elmer and Elsic. In 1978, fhcphilompbcr Danid Dcnnm pub1ish.d r short pi= d c d 'Why Not the Whale Iguma" that l i k r w i r argued in hvoc of studying whole simple ryrlrmr dirploying integrated mion, wndng, and planning mutine !contrast this with !he stress on imlolatcd a r m s of advanced carnition such az ‘hen plapot&.'lorr vudorfrndinbsn:l medxr.dnapnori,. dfrpla,d lhr rlss. 3 . ~ snnnrosl 1 ~ntrUngrnrtr.r(:hapan Iand 1 , Onr pow&. for S U C ~ ~ w t < h , s s w chave n r t d bcforr,rr than h ~ n l o y ~ a l l o l u t ~too n s~ + ~muwadrm<ed w
,
CHAPTER 6
804
ROBOTS AND ARTIFICIAL UTE
p m b h may wdl he pmfoun* shaped by ~ r n r i ~ t.olutionr i"~ to mom bui pmblms of lmmmion, -sing and adion wlmion. ~ o m w rthc , id- t h t i t is himto wprrltr b u * functions such u *Lion, plmning m d action taking is itwif open to doubl: thee functions 1.r vc dro ww in the ~ r n i ~chepter) ur look to be quite int~rnntelyintenelated in lurunlly intclliwt syrarns. h m example of rhc whok sFtcm rpprm=h in action, ILI us consider (partly by way of wiqBmoW robot$ are a nice, but o&. a m p l e ) Batban whb'l m t workon cricket phonouxir. Fcmdc < r i c hu c abk m idmtilj s m a l c o f r h c m c s p d u by his ~ n g a n d m able to ur the darned rong u r signal rlla*ing the hhto 6nd the male. The t n m "phonotaxk' name lhir capcity to deed m d w l i ~ b ymove toward a s@fic sound or signal. The male cricket's song is p m d u d by rvbbing its winy together and
toward it.
n b w y o f d ~ t i h i n g t h r p m b l a a m yh, h h h , h m i r l n d i n & d f f f f f inansingly hmiliar rcrronr. Tho hnr-loulirtlommote mutinc m u t i t u t u I nat urk dmrnpoaition and identifies a wquenc. of rublarks that would phimly w k the problem. But it i s again h m r g to 1 nonbialogird *Lion of single lunrtiondiry m d wqucnxid flow. Webb, hearily impired by what is Lnmn of ml cricket analomrand ncumphpiology,dexribcs the folla*ngalamtirr wrnaria which w succnrfully implcmrntcd in s mbol cricket. Ihc ctichc~lnnace on its foreleg. a d arc joined by a n inmr rnchcd m h that alw opnr to the world at wo other p i n t s lalldi p i ~ l an ~ t )h e h d y l e e F i p r . 6.1). Encrn.1 mund. thus amn at each n r "is n o rout*: the direct external mute (sound source t o n r ) and m i n d i r intnnd ~ mute (ria thr other u r . spiracle%and tnchnl wkl. Thc timc taken to tnvcl t h m u b thc tube rltcn the phax of the 'innn mute" round rciativc to the "outcr roar' round on the tide 1r.r nraml m ihr mund mume l-#n'e mund ann#nlni h c n r dowr to thr ex. tern81 murw w l l haw trawlnl r m.rh shnnnd#~!rnc.thrnmund r n t n n g n the men, n a thr onno mulcl As Ircrull. nmok ncvnl or c l e a m n ~ ' l a u l l n cam he uud to rum thr oul-of.phuc ~ " " dw v n , yielding s vibntion of grcr,rr rmplit~dc( k d ss a louder raund) the crr nearer ,he m n d rourra Odentrtion in thcdiwction of the male ikdimtly mnnolled by this am. Each ofthc oro in-
.
Roban and Artifitill Lik
CHAPTER 6 1 ROBOTS AND ARTIFICIAL LIFE
ro6
trrneurons ( o m c o ~ l l l e 10~1thrar) d firewhen the input (vibration rmplihldcl m c h e a critial lcwl. But the one conneed to the em nearest the round rourcc will reach this threshold 6m. The cricket's nrmus *ton is ~ cup t s lr to wliably turn the rrickt to the ride on which the d4icrk-d inameumn fires 6m. As a result, the irUgt rerp0ndr.a thentan of each burst of male sang, by turning and moving in thc dimtion of the mund (hmrc #heimpartanre of syllable mpmtitioion in attracting. mrtcl. Notice, finally, that in chis story the pmiculariricrofthc Ira. chnl tube an crpecirlly crudd to rurccu. As Wcbb puts it: o n < o f ~ f o n d r m n d p . ~ i p l n o f r h " ~ l rirUlll,hrmks'.uxhrJruhctnnr m mhs mundr of Ulr d n d nlling sang hquenv. and the phaw shihs in this lnnr mt&n arc ruifd lo that pmieuiar wlwlenhh. (Wrbh 1996. p. 61)
The result is that the mbot cricka (ucFigurr 6.21 d m not p o o m any .rm oolm~hchmlm for idnifyiying the d i m i o n ofsundr, nor don i t need to rvtiniy diurirninntc the rong o l its own rpcricr fmm 0th- r o n p For other rounds m ~tructurallyinrapableafgmmfingfhrdim!ianal responu.Thembl cricket d o n not ' t l d h" rrilnrin. oummc <.a.ritin lrurh .r mtrcrn recom1,ian ~. ern& " end l of mate detection: inread. i t e x ~ b i t r ~round ~ - lotalizstian) , tn !he r w ~ i rcase highly qqicirnr bur (indnd, brcnuse) rpdal-purpow rrrotagirr I f d m not bvild P rich m d d o f i u mvironmmt and then apply s m e logirodduairc infermcr Mtern to gcnrntc action I,dm not nm p-. a central wnrary info"".. tion starc upiblc of intepting multimodel inputs. As r mull, it is not at all obvious that the mbot rrirku c t s mnvhing wonh ulliqinternalmprrxntaBonr Various inner narcs do rormpond to salient outer pnrnefcrr. m d certain inner wtiablrs lo motor output%But Webb n r y a :
.. .
~~~~~
~
~~~~~~~
~
I,
k rn nK-vm ur this ymW* inammnim to -!in h a t h e m m furxt i o r k h c r k b l n r r m r mtchanirrl function inionnming-anromoton.r rde
rpi~tml@nlly mmpanblcto the bnnionof thcgcmronnmin~fhc motomtothe xhrrlr. [Webb, 1 r n . p . 53) I n fact, undmmding thc hchavior of the mbot Dirkel q u i r e s ancntion to details that (fmm the rnndpint ofclrssicll cogniriw ricnrr) l m k much mom like dcrcripcbna of implrmenlafian and mvinmmenttl c o a m than rubrmtiw features of m intdli=cnl. inner contml mlcm. K l v factan includc, lr noted. the fixcd.lengh m h r a i n d thrdixontinuiF(mnd reGirioo of the m 4 rong Theexplanation of ml.lifc critket phonotarir. i f !he Webb model is m w h m near cor. rect.1 involver complcr interamion among bnin, boiy, and mrld. with no ringle compancnt tearing the brunt of the problem-rolvmgburdm.
One major strand o f m r k in a n i k i r l life lhut a r m t h e impomncc ofredtim, real-world ~ctivityand the distribution of problm-solving mnhibutions m r r body, bnin, and I dcnvimnmn. Another strand. to which w nowturn. nriuum concerningcmccgcgcncc and
CHAPTER 6
106
1
ROBOTS AND ARTIFICIAL LIFE
The m l n m.mughly, to ny lo stay nnr r marr of orhn bids, to mstch
wm vrlarity to that of your neighbors, and to amid grtthg too clmr to any one neighbor. Whm each b i d folloxd thew rules, patrrmr of on-srrm rnivity mm d that q u i t ~ d o ~ l y r c w m bthe l d OaLing behavior drcal birds whwling6rh. md o t k r animals. Widely spaced hoi& immrdiatclyrlscd mnb,thcn p u p m o tian ensued with each b i d making rubtlc sped m d position rdjlr
.
me
,.
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ud.. 1994). The monl.oncergala is h t r p psrolthl complex p m b l m rolving need not a l w p inwlvc thc luc ofhnv-duty jndividurl reasoningm g i n n and that mcrdinrrd activity need not be r o n m l l d by a central plan or blueprint. nor by r d n i g m t d "leader- In t k trrmia stvdis jw dnctib4 no tnmifc lrnovr much a rll: imply how to rerpad to m mcountered frarwr of the I d envirommr. rvch la the & m i d trace in the mudbaUr. Thc mUmivc i d v i t y i MI m n orchesrtnrrd by @ar r i p d i n g or rommunirptio-instad, S ~ are ~~ hL ~ ~ ghrough d e dthr r n r i m m n d nruc tur~~,wirhoncrgnt'rworkpramplingsnoUl.rro r..pnd*~o.dingto wmr rimplc rule. (In Chapla 8, we will dircwr some dowly n l a r d idea in thc d m of r d n n r d human problm ralvingl. l n rum. workon artificial life dm m m n f i p the ~ wirna. of the mind by rnphrunngthr ~mpon.nccoll~ctonnhnth~n rrh. ~lultndudmmpuunonmd rwwron Thew fartun mn
~
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~~
.
.
.
6.2 Mactlssion
* THEmmANDmAESTRACI Work in arti6"aIUh and m l - w o r l d m M a o R e n has. n t k r ndicrl M r . This m d i d m manifnu irsclfu r ptinripld antipathy toward (or ar lraata~mr*ism abut) the i n w t i o n of i n m a 1 rrpmnations. mtd planning, m d rich innn m d d a in c o p i t i n u i m r i f i ~erplmrionr of intelligent k h r v i a r ' Such n d l o l ism l w b howewr, romwhsl prrmafurc @cn thr sate of the m.For the wtiom of internal ,ep-ntatian, inner world mod.1. and their ilk w.rc intmduced to help nplain a nnge of khrviorr t i g n i f i ~ d yd i f f m t hom tho* atudird by most robticbn: khaviom ruocialed with what might m ~ o m b l ybc ' nlld"ad. n n c d -on: Stxh bchrvion inmlvr, i n p.niru1nr: I. The mordination o f utivity and choice with diiel, imqnary. or count&ma1 *,a of &h.
I . The mordnnatnvn of anmty and
CHAPTER 6
8-0
/ ROEOTS AND ARTIFICIAL LIFE
I t is t h a t kinds of behmi'or, nthfhcr than lrromotion, wall bn04ng. mete dctution, and the I&% for which &t rep-tationalin sppmnrh seems bc.f suitd. Thus consider the fist class of nu* ~ h oc n e involving thr cmrdinalian of sdinry end choice a m mmc kind of physiol dironneoion.4 E m p l u might indudc planning n u t y n f s family vrulion, ploning the likely ronwqumcm of mmc imegined c o w of action. using m m n l hagrnl to count the number of windows in p u r London apanmmt while sitring rc your desk in St. Louh. Misrauri, or doins mcntd .rithmetic. I n dl rhcv -, thc obimlr of our cognitive s r l i v i v r n physiuhabsenr By mnuut, dmmr d s t h c r a m inwkcd by the nor mboticiats involve brhanar that is mntinuously driven and madifid by the nlen n t rnvironmcntal prrm.rcr--. light murcc, l c phyrical terrain. the n U of the mdr ctickn. *r Yet thew kindsof problcm domain, it rermr clear, rrrsimplynar rufi~ienfly"repmentation hungry' (Clark and Ton%io, 1994) to bc wcd as p n of any g m m l sntircpmrntationallst argumrnt This b why the k t examples of ~ m m t a t i o n - r p - red-world mboria rdke ur rr rather poor -plnofgmuincly cognitive phmomena. Rrndigmltinllymgnitivc capatilia hvnlvc the abilir, lo pncratc appropriate artion m d choice dapitc physical diuannmion. And [his rwuira, mima facie. the uw of mmc inner item or omces whaw mlc is to stand in for thcm*tingcnvimnmoltnlrta~cofaRairrandhrnrerosuppan thought and action in the abwncc of on-going mviconmmtd input. Such inno stand-ins an internd rcprcsnulionh as trsdirionauy undcnraod. Thc p i n t h e r e t o br dm-is not to argue that the updry to caordinan action dnpitc ~ h ~ idiwonn.nion o l ,trirtly implia the pramcc ~r~ylhi,,~ tnditional intonal rcprc.entaions. For it is cenrinly @s$ible to imagine G c m r that .
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tinarc tho= that fill dimnlr under n h,n i u l l a m . Thus ddminc lishr inrcnrilv is ~ ~ ~ , ~d a m i n s r nomic oroorm. ~ m a n 1andolh.r s mimrlr). are..however..cmahle of u l u t i v o s p o n w to '"nonnomii" pmbnies such rr "being a <mmpled shin"--.
. . .
chemical p r q m i c of r Piuraorre&us aomic, whmasth. p r n p r t l o f - k ing admired by m y . L not The propcny of k i n g vonh r million do1Ial.n ir likrwir noonom+ is the p m p r m (according to Fodor--~rr t m ) of bm. a r m o l c d shin. The D a n . of the a ,h n i o l univera. Uut .re. i n d d . m m p M ahinr arc ( o f ~ u r chUy ) bound by physical lam. But such Lam n p p l to ~ t h m not bemuse they s n crumpled rhinr (or evm shinrl but ben u w thq, e.&, r i g h 2 p u n d l or have such nand such r mrn, ac. For a nice d i w v ~ i o n d t h c iuvnrriringfmm Fndodor's anme-ion that u l m i w r e . spanu to nonnomt pmpcrtis b the ceh value ofthe uw of mmtnl mprcI C ~ lany m d Lmnc (19911 m d Fadar'r reply in Ihc rsmc ""I
~~
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p r o m that (unlike, e.8.. the shin's -1 don not charrnerirc the o b W in a m y caprhlc of figuring in physical irws. ~ i n far o 'being a genuine ddler bill* or '"king a labour victory in the 1596 clmion." Fodor'r 11986. p. I41 view wr that "wlmivc r r ~ p n s e to [such] "on-nornir pmpcnirs L the great cvolutionuy pmbIcm !hat mental npmrnlalion m, i n v m t d la rohrr" The nomiclnonnomic distindion does not. h o m r , fully Fndor'r p u r p w r . For i t is d n r l y porrible to ~ r p o n d wlcl~tivclyt o "nannamic- p m p n i n such as'd~inncu' (wedo i t all ihcrimc). lithis h to be physically explicablc,thcrr m w t bc mmr kind of (perhaps complex m d mul!ihcsrd) lawful relation linkhg our reliable xlcctive mpanwr toshin-pmcnringdrcumstanrrs. Thc real iuue, ar Fador (1991. n. 2571. mow recenflv admowled=n. " . is nor whether shirt detection bllr undrt law, but"thrt the* ir no non-infenntial myofdetming ihinnesr." Thc d q isrue. u Fdodor now seer it. thus concern what we m a t nll "rim. plc xnsor, tnnsducabiliry." To track. praprly such .r "king 1 ,hi"" we wcm to n n d to uw m i n d i m r o u t c w directly mracka~omplcrofoekr fnturnthtil v ~ r cumulatively signifies~shinhood. No o~n. could build a simple xnwry mnduccr lwherc a trsnduccr i s looxly conceived =a a device that taka sensory input m d conven, i t into a dificrrn, rormor "4for funher procluing) that (men roughly1itsrlf irolarrd dl and only rho~ce n c g l psltcmr thal rignifi the p e n c e of A i n r Inn-d, wu nmd lo d a m the ohtainine rs "is shin " of mrooeflics SUB ~hrpcd,".could bc worn hy r human: c k . m d then (or u, ~odocinsiru) inferthe prwncc of a rhin. I t is thc p-na of infcmd rcprncntstinnr and thc -dated
..
~
~
..
CHAPTER 6 1 ROBOTS AND ARTIFICIAL LIFE
1-4
changing n l v c rdlerrs chc intmctive result of the rnivitirs of multiple ynemic elmenu. Eumplcr indudc thr trmprahlrc m d pmsrvm of 8 gs* the n l c o f a c ~ cclcntion and dirmion of motion of rhc crowd. the amplitude d t h c c o n m i o n r o h m d ro on. Dynamic wtm t h m v i h i r h wr will intmducc in the ncd chapter) spnalizcr in plotting thc n l u s of such coUetive vntisbln ra mrmt khauioiar unfoldr over time, and in plotting the mlationr between the r o l l ~ r l i ~ ~ variablesandm y conno1panmeten (such as the tempcnturc ~ d i e nin t thr oil). An cmogrnt phrnomon, accordingto our tint accounr, is chur m y internring khauiorthrt rrircr u a dim" rnvlt of multipl..arif.owniring s"(i paritivc fedh c k m d circulu uuwrionl i a m a i o n r acuningin I syrtrm ofsirnplcclrmmts. ~roblrmr? m i r now works well for nstcmr mmoridna " lame " n u m k n of cs-tidy idrntiol clonenu abriing simple rules. B rhw corm flocking, trrmirc nut building, canvenion mils. el<. But it is 1- clearly applicable to ryrtcma mmprism$ wlatively few and more hacrogrncour cloncnh (such 1s the r o b t cricket m d the bouncc and veer vlll foliow").
.
L
Emngmsar U~pmg~~rnmrdhnoionalir); By contrast, the idea of rmcrgcncc
u snmhing like "unprogrrmm~dfunrtionalih* ir tailor-mdr for thc smblcm nm just mentioned. I n rurh w vc o b u m sdrptiwly valuable behavior arising as a m u l l of the irenaionr b c m rimplc on-borrd circuitry and bodily and cnvironmcntrl structure. Such brhaviorr ( d l fouowing, "ickrr phonatuh) arc not suppoficd by explicit pro-ming or by m y buy "sgcnr-side' mdowmant. Inrtnd, they ariw ar I, kind of mide-@ar of some irrasrd mqurne of agent-world intmdonr. The point L not that such khnvion arc n-smrily uncxpmcd ar undeaignrd-nr mbotirkh may xrll nout to =chi- their goals by or
.
3. Em-
-
as 1 n t m . w Camplaity Ithink m can do some jurlxc lo bath the
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NONLINEAR INTERACT
..
A nonlincu inrrmction i o m in *hich the du. a xna lapropambnlllg to the w l of ~J IMld,x may (for a m p l e 1 remain at rcm
vnfil~rra&rdd&rmdthminnarun+vithminuav in the nluc of y. The khsviar of a -dud c o r n d o n i n unit (m Chap tcr 41 ia nonlinnr sine the output knot the rrrightd nrm ofthe inpuw but ma). involve. thrnhold,aep function, or other nonlinnriIy. Aw1-1 example is r w i t hauin~ m o i d tctimtion functioa in h i c h certain .a r i. i n p t n l u a (hi$ pairivr or negative d u r s for namplcl yield r rhup re. rpons uvring t k unit h, output 0 Ifor high negative input) or I(far hi& pmitivc input). Rut forcerlain mtnmrdistc input n l u s (mildlypositiw or udly nc@tive 0 *Pam. ~ d d iny o the a r n, input. Sle Pi,
80 .O h l a neplorr tnpd 4% n t h I to .O b& p rm.n m05 Am m p u 8% r r a d n t h rvblh &rvd mpr.- (0- d i n m & v nl,*&pmd fmm flm.0 n 11 1% Fag, 2 1 p 5 1 ,
nth0 t k
t o < o m (obtain) in dcgres. Phrnomrnr that dcpnd on r m a t c d iinnr interwria- with only Jimplc liindr of fcdbsck loop 1c.g.. a strict ionpan1 wqurncc in which xaffmr ywhich then affms rl will munt u.s t k t , only m l d y em.rgent.
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N U U ~ r y q q .nun iaho p~qunpus wroj mm (mqr!pom FIEJO e 2q moq y p u d 01 m rnfiop ( s q q v - '0~n01 Sun!oldu l q ) r q nrA1vur ur 01 squmnnr *qd~ o'ucm~uuoj j nor u o ! w * u ~ ruo!mlsyl pmmjo rwnr
q d ~ 0 3q 3 V W W 'RuPpUnq W O "yl Y?IU!W PUI 31-D A V IUI m a d s ,p!odomr) qqodomr n p p n r .~un>ey pm u e o r d rwo mr uo mjr m q s rsq10 --or l p d o r d sm j o n>unru!n avnol OI g p m "ylo PUB = ! Y O X B ~ Iyl ~ S " ! w n s v n r r m d pus a u a u -w A p r p l(6661) urpgl pur I696ll I % ~ ~ M =S-&U~ IX 03U1 134m .10 Y09mtWWU13m YO D3my113UO . . . . '>ldZOJ U@!lpJ>p e W!>W~VUO?10 *IS- ( ~ ~ ~ 2VJO 8 1 0 a!nlurduA r y l mol)) qgru!prrdun m ol'rAmjodvurn rl!uyrpyl ur u! 'Alawd .add* p o d n ot ~ h p d n ayl-.uo!md~ ilddnr. n )o u o ! ~ e !a210 ~ "41 "1 .uo!l"!ldx-jla s. u ! u d m d %no- j o (srr -d 3661) n m sdeqnd puc ~JOJJO uo"!mpp ~B~>JJ>a q q ~ l m m .uaq .alq>p mg
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.%u~plojm q d o m m w aql jo adryr r q l 0 ) ,mm a63 J! uo!,cp~sE lV ", JOJ ,mm!lrqnr 0" n u3yl %9e, 'gnrp y l p n r ul .I! or rm *A$ I ~ ruquawu! I r y l 1 1aqapou ~ ~q A ~ Y D'pv yl ,z! P!P ->ld M o ~ Jrip0 ! pWJ!lu%lS r 38-S 3 0 3mlEaJ ,!luald~rWU!Jap myl ( M .d M ' )I n q q (ydur 10, (.9 xw 2-1 ."w-'wS Z B = > ~ I ? I U S w a >wql)o ~ o ! u r r a y nlduro> l aql lo uo!repqs a ~ ! n b ldl alelroum =urnjo uourn!pwd q q t ~ q x o % p 4 p d u p ~ 1 - - ~ q qU nIq!s ~ ~ J J I U O ~ ~ ~ ! ~ ~ ~ ~ I O J ~ U ~ U I a o y l n ruawouaqdru>Slrwrjo nap: In ! v .=I"B~J=x~' Y ~ Xaqx UIp n w - d a a>w%~lua j e arux (rua~rg!pq n b ylnqr I puc) lrqtoua >rooppoyr I'(n3u -.uldmo,jo 3~ 2q1 l o j pur) A p ! j ~Xu!plo~nn ttqnnddmun m muSuw3 1
wau ayl jo nunusla p n w l x rpnpl" A m 20 wads r y l ot p~uauoA n o v rq rr>Iq p m u0v.J q>nS alrc] p m Fluuy qdtrlnw Jo WOnlU2lul 2118 UOJJ 8 " l l r n ~Yl l . l l d ."I *,.I, ll", , . L m . U ( l o , a l l e r .+pn,.r>An,Y"m. I"'" A.ul
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' w d w a l ( . N I ~ - l o num&q zpm) ~ y u . B z qtppmuzndwo= o ~ 3yljo k o -uum ryl u! proxurldur! r! mqsh 2 ' ~ %."!Ado> urumq Apruogrm pur mop -nnm tmopuu q.+ S u n p 03 ua!qne a e pur (Ado,) a>nparda un .mr!dro. 2 U . T n d 3 JOJ 2 l d l o m (unfiord pm5Jo p q saw0 q l u ) m ! m d l o ' u r ~ ' ( ~ 6 1 ' 1 6 6'Aq) 1 s ~ m ~ p u r r u m ~ i d s o u p n 'rldurmrmj'~rp!ruq) qaq ~rwa&m pxrg-lamdurm 10 a q m n qmt qpw ! e n ~ ! uY!~ (p1)pou Ald
pe'p
CHAPTER 6
78%
I
ROBOlSANDARTlFlClAL LIFE mentlUywmn-bawd maritionsand ihr g.rrpofU~eabrntandthcshalnttrhrr. n d m n v of .dnnEcd mpi,ion? Balancing rhuc rxpl=natory n& (the n e d to arr continuiry i n oatum end the nnd to ippmiatc tho mental as somchaw +all i. map the hardca p n of w e n t c w i l i v c wicntific smmpm tn naturalize h e mhind
d r m e n t u h r m i o l or compurrriontl-that otalyrc their o m pmduflion kom milabl. m u m a - - e Kauffmm, 19951. ulf-rqroduaion. generia, and mceb. olilation (C.dr. 19811, and rn on. A very ml posibiliy-lra m m t i o n d by Bcd m 119961-ir that "life" is s YI-UUC~CILL(ICI cancrot. involvin." mulridr w i c d . fesurn none ofwhich i a individually necrsllyfnr i sottm lo count i r dive, m d multiple diffcrmt ~ubetsof which could k sufficient. There is 1Lo r debate about the rc1.tionr brlwnn life m d mind. one w y to min thcuomy IucSedinn A1 that thrlcdmple,lif~-lkt~amteIl u9linle about r n l l y roplitivrphcnomcna is t o hold that life and mind share d e q org~niulionsl
.
. ..
Life and mind h m a m m o n abanrt p m m a wt ofhuic o r y n i u h d pmprt i 6 The bndanalq papnin
This,rr Godrrry-Smith note. ir t drep claim about the phenomenon of mind irmlC I t thus goes bcpnd thc mom mrthcdologid claim ghat !he wientific invntietion of mind should p d by lookingat whole. embadid life-formr,md acuruthatthr cmual haharunn*firrof mind a<, i n largepm,rhow oflife ingmrmd. This is not to imply, of munc, that life and mind are r m l y q u i d m t - j u r t chat if w underatmd the drcp organizing of life in gmcral. wc would have comer very long way i n the prqlm of undemanding mind. I n marc mnr n e tcmu. thc thnir of strong continuity would bc if. for rumple. @hebrric mnccpns n e d d to understand the organization of life t v m d out to bc x l f organization. ~ollrctivrdynamicr, drcu1.r cauul pro<-. autapoie~i~, uc,m d i f tho$< v y r a m r m n q o and mnrmrnr turned our to be cmml t o r pmpcr ximlifir undmlandin# of mind. A s p < i f i ~ - ~ d c u m t l y quite popular--wnion of the nmng continuiry theis ir rhw !he idea rhrt the concepts m d conscruar of dynamic systems thcoy will turn out to k the k t loalt lor a wicncc of mind, a d will simultan~ourlyr n n l the fundammtal organiutional rimilatity of proapraring r c r w multipr physio~.cvo~utionary,a d trmporal Thc danger, of coune, is that by ~trcrringunity m d similatiry wr mry lose right ofwhat is spnial and dirtinctiuc. Mind may indeed panicipaIc i n m n y of the dynamic p m r c r a rhmderirtir of life. But what about our old frimdr the funds-
6.3 S u g p t d R a d i n p U u l u l m e d inlmdwriau m wn* in rabotlcr and utiArY lik i d u d r S Lnl.A m f i d
1
Llf< Ibndon: Gp. 19921, a p u m . l i s ~but I ~ solid inlmdunion lo thr hlmrfand prsricc of imfirial hfc, and S. Fnnklin. ArnrBI Minds IGmbndgc, M h MIT Pms, 19951. C. b w o n 14.1. AnFMlLf<:A#OrrmoriC.mbridy. MA: M E PRU lWSl ~ r i n u t h e fin, thrw b u n o f dejournd Ad,6tio'iLftmd indudnexmllml, ~ p c i . l l ~ a m m D i n n l o r ~ c arn i r l n cowdm robolicr mllmivc dicrts. ~olulionar* nmulnion$. and mom. It vlrludn one of my's p a p s on the Ticm prom. rr nll u txccllmt htmdunrnry awwiews by lrmane m h i l Luc Strrlr Pae il Mas. and MiUhrlRanuk. For an e m l l n lrnlmmt olfhr ,sun mnrcming mmqcnrrnndm!tmir lffnR ihr mdcr ir ~,mn~ymmun$~tolookstM. Rnnvk, T w " r~,miVradTm,plnm'lUm~ bridge. M h MIT P ~ N I9941 This is a drlighlful, l i m u h i o l l . k d ilmdu(tim to thr emqrncr ofiomplrr dierl$ from the inlrnrl>vn ofsimplr ruln. bfrrvr is mnilaMc on
...-. .
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or th. phololophnnl w,u n a n i n l mqmn, npvnmam. anddr .&MI o l l ~
m m o d , rr w m o NIP ~
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M. dm 1d.1. nrPhilowpnr o l . m f i . ~LC ~ word. ~ n -
dznd.imod unu n t n ~ m s ~. o a ~ , - ~ ~ m Le. ~~ # ~~ ~ . h~ v~ D ~ I ~ . K ~ . ~ . . Mdm. A tlark. ~ n nm n ~m , n t ~ w n nod) . and irisld roprnnn ~ p i m ~imhr~dg. O W UIT Para. IW7 ,t a, m m d 4 crealmenc ulmsnrof i k c n r < turn lor workan ml.rrrl4 &?,:I o d i k impon~uru/phnftol i r n p l o m r n m ~ H.~ Chd .llJ R Rm 'Thr 1m r. h n 1 hdy ' Ttrr.45 01 FMOYIC:,, 20. WSW?. IW7 Ihi. ~ninrxcellml$'aon,urnman u l o i J ~ x e mbruro(trc.t.na~hr wmusrmrm.hodv.snd , mvimnmrnt rr = unied +em. n. ~ m = m r . x k~ n l t r n c.gni"on: ~l CD~PYXI~~OMI Mind, (8 rhr W a l l (Chicagr Univrniv of Chiop P m , l-5) k 8 wruarruted phdorophicrl i w m m c for vlnnng thc mind u nwntially mrimnm~ntrllyemhddd, and B. Wrbb "A CrirXIf Robot." Stintifir A m & 275. 62-67, I W b is a uwr-friendly .ccoua of the uork on the robe, <"rik
.~~~..~
bridge, w
to find a w i c tmlr h e r suited to thc sndy of m m p l n intmctivc sysmr. Whrfhs such twlmla oKcr m ou+md-out alrmurtivcto l c rndi!iond thmmtiul hamwork, or uc b n t s urn r a kind of subtle mplrmmt to that b m m o r k , arc mrcten to which M dl wxrn mum. T h e fint order of bvsinru is to rlnnfy what a dynamic approach i n w l m . Dynrmic systems thmry is r well-mblirhd framework in phyricnl wience.' It is ptiMlnly geared to modeling and dmnrbing phmomrna that i n v o k vchlng m r nmc land change in nrc of chrnggeowr time. a d m on). Indeed, the brand^
~
~~~
hibit a renain kind of =amplodtythrc the tmhhniul appsrstur of dynvnic ryxtrms & m y mUy r o m n lnca its own. Some of the b y haturn on which this r p c l d kind of uplvlatoy power depmdr include
7.1 SketchCornitin uicnre, we haw -, ir involwd in in MI.,ing ICtl.ll fmm th< im,er "p"l.31: r kind of inncr symbol flighL The oti&.L computr tionalhion (Chapters Iand 2) displayednosuch quslms and happily tird s p t u t o wmantin ur ing static inncr itrmr that could *rnd for wmmti' cantmu Such itm. we* innrian, (*,oh i d ~ n t i d " am011 ) diKerent contlru and s r r carilylhovght of- inner ~ b a l r . C o n n m i o " b I I p Ir(FMwn(l p-ha (Chapter 4)txpandadourmnceptionof ~hc~rarlwmantinlmk,PUom'ngmnton-mritivc cwiitionr of unit *flinty to bnr thc m a n t i c bundm and producingwnsiblc behaviors and judpenrr without the uw of static, chunk, casyto.interpmr inner star= Connm#ioni%m. WL might rry, s h o d us h m to klim in inlrrnal npnunrationr without quite believing in rmditiond internal spboh Rmnt work in ncurawirnrc, animate virion. roboticr, m d anifirial lice (Chaplm 5 a d 6) hrr opmded our mnceptiona atill hmher, by divlapng an m n mdcr mnge of nrvnl dynamiaand poviblcrodingimt+aand by rtrcsingthcprofound r o b o f t i m i n k body, motion, and 10-1 mvimnmrnt in bioiogicd problem solving. But rr thc mmplrdty and cnvironmmtal intcractnity of our ~ r o t i linaerrc, r so thcaplanatoy lrvengeprnvided bythcatigiml complcr oftharclial notions (spdmls, internal '(prncnt~tions, computntionr) wenu to diminish. W s m i r sysrmr theory, as i t is uwd in rrccntl rowitirexien<., a n k sen rr m l l l m p l
,.,
I.the diwavcry o f powerful hut
im-diimmiolul dncriptionr of systemic un-
folding.
2. the proviion of i n t u i k , gramcrric images of the aae Wcr o f the system, 3. the ( d 4 wktrd) p n d c c of isolating conndpmmnmand defining m k tiv. m"'2bla (wc klow), md 4. the u of the techni
Trrnrporld into thc m p i t i v c scimtific domain, thue k t -
mrkc dynamic approach~ o~ p d d l y a n m i v c for undmmdingchovupcrs ofrdrptivc behavior th.1 d r p n d on complex, cir& a d exchanp in which mmc i n n s h*r i ir c ~ l i n u o u r l v.ffcdinp and Mnc bv mmc othcr linmr or outer) factor "~ f f c c t d y (which m y iurlf atmd in similar &lions to a factors snd so on). Such com. plrr
-
COK I: Rhythmic Finger Motion -
.
Considertheore (Kdlo. 1gb7.1995.Chapmr) drhrthmic f i n motion. ~ Human subjmr. a*ed to move their two mdcx finsen at the r a m frqucsg in r side.* ride "wiggling' motion, display tvo stable matqies. Either the fingen move in phase (the q u k ~ l c n muscles t ofcxh hand contrrrt rt the same moment), or n. anly anliphas= ( o n ~ m n t n a. ~ sthe othcr expands). rhc antiphas.solution, hou NCI. is unstable at high (rcqucndn ofolcill.tion--rt acriti-1 fquenq i t m l l r p s ~ into the phased solution.
CHAPTER,
116
/
DYNAMICS
mnmmt b mrrrvmd ( " e d - 1 . internal reprrvnlrtionr mated, mmpuutions prfomed, m d an action c h m . me om11 dmcc mflmr a nicely d-ompmable p m b l m solution. For it rnpu r division ofthc pmblrm into t h m distinct rorh af which is d a l l with indcpndmtly, m d which am cmrdinated by artr ofmmmunirrnan (in which xtclla g the d w ofrand a en), The fnrum distinctive of thc mmputationalgovernor am thus Ill the u x of internal nprcwntations and mbols. (XI rhc ure of compsationd opraliaas l m dlcr and t ~ r f o r mrhow rcpr-t.tionz, 131 thr prruu~eof a wcll.ddned precptiolt computation-adon q l c (vh* nn ttlder d s " ~ q w n t i dand cyclilic ope=. tion"). and (4) the ~rccptihilir(to #-wire infomution-pror~oingdrmmparition (what rn Ccldcr calls "homunculmty"!. Now for the -nd aoludan, thr one d i m & by l m c s Watt (m Figure 7.2). G a r a mica1 inm the flywhhl m d antach fwo hinged -9 to the sqindic. To the m d of cmch arm, amch a metal ball. Link the r m s to the throttle VZIa thrr the highcr the urns swing uut. !hc lro steam is allowed through. hr the ~ ~ i n dturns, l. 'rnnihrgd force cauur the o m s to fly out. The h a r it rums. the higher the amr lly out. But this now ndum seam llw, causing the mttglnr torlowdoxn and the armsto 1.11.~hw,ofcourse,opens rhcnlvcmd dm more
~
~
~~
~
~
~ l r n t r
"7
Thb ccnhifugl govcmor, v m Gcldcrdrims c a ~ t u t a ronlml 1 spttm that
is noncomputarional, nonrrpresmtationrl m d that rimply cries out far dynunt snalytb and understanding. I n particular. only a dynarnk analpis o n explain the p u l i o r l y romplcx, yet rffectivr, rdationrhip that is obtained bctmn thcsm m A mad-dog rcprrarnlationalist mighr, pnhap, ty to claim that the k t way to understandthis relationship is by depicting the a m angle as 1 rep-tation of thc cnginc s p d . But, urn Gcldo (1995, p. 3531 insinr, the rul mlslinnship is "much more subtle m d
glr and ihc engines@.
.
-.
'Lr W m n .od Nonanu ,lW. 'For m.nvk.Stwmd G d W w r
I!w*l md-
Llwtl.
~~~~~~
~
~
CHAPTER 7
830
/ DYNAMICS
Coruid-following Pollack (1599tlhc hirmry of flight. When ue first m-unto. bird! and wonder haw they manage to fly. thc most rupcrfi&lly mlirnt fnturr might wcm to bc ihc flapping of wings. Bur, u wc aU now h a w , rind as w,mr arb pioneers found out by bin- experience. ppowrivl flapping i s not m l l y the key Inned, a%the Wright brarhcn finally Fly& out:
"w?, of the pmMrm of fl*g i s in finding. plrrl within the wi8htiriu dimrnrion h e r , gliding i s paoiblc. and getting the cosml ~ t m for s dpamial quilihrium riaht. ~hr~rnmulsirrmini, hut in a l l i t s luriuumms it blorlv . FI~ppin~isthrI~.l~irrr. .. . . . our pnmtion. (Roll.
I,
...
I:ndmtandlny 1Ioa1 m l - x ~ mphnlnl r r v r m . P11l1a.k klmrr. 15 proty em pouiblr i r long as wr focul on rrmbolic pmblrm lolnnp Iflappingl. Inmrd. w snould (Pollsir. IWI. p 1191'unsh 1og11111113 13th CIIL~C" OWL "01 d l -soh. wsrr law' but 21 ohnirsl law Onlv ihrn wall we k i n uc hoe Loc~lnxocsl iqlrl. , " ligencean be rr robut m d flcriblr rr it i-how, far c u m p l the ~ injured cat a n immdistcly adopt a rucreuful t h m - I d grit muncry ofthc rompln. inrcnc. tivedynami<~Linkingnrunlnets wirhrpring-likcmuwlc a d tendon syrtcmr Such rich infcnctivc dpamicr haw linlc, it wrmr, to do with symbolwing problem dving. Yu it U this rich nonsymbolic s u k t n o that. i t is argued, forms the cscntial basis for all aspccls of biol%ical intclligmce (see, eg..Thclen and Smith. 1594, p. u i i i ) . This rubrmrr. u we raw, is rharacrrnud bypmcrrrr of continuour r~ip-1 crud influcnca in which ovcnll interaction dynamics (nth., than rome privilcgd, knowledge-bad componmf) mrhlc thc orynirm to .chic"< iU 4,m d to compnsat. far vnwrlmmr cnvimnmenu1change$. I, * i n thU mythat thc Watt gnwmor. .lthough dcorllirwlf a nonmgniti"c derirr. maybc p m l d I n n Gcldcr, 1595, p. 3581 w'morc rclcnntlysim~laiin ~tsopention to Ithe hmdrmcn3,dynamir~lsuhstnteoll human cognition than more traditionel
.
8. STRONG M D W
U CONTINUITY
The radial their ir rooted, thm, in 8 hmiiiir obremtion: fhr s h r p end om.tion or higher l n c l cognitive pmcswr haw pmbably heen built. in rcmc highly pth-dcpndcnt fashion, on a more ~alutiansrybasic r u b t r n c o f ~ c p t i o m nd senmrimoror
ilar points as have thmrinr working in tnditiond mificial i n l r l l i g m (e.g., Siihcfundsmcntd framework mon. 19%),mddono so ~ l h o u l o l l i n g i n ~ o of compmtiand and reprcwnrationd nplanatinn. Where's the d i f f n ~ n d diffemnccnpin lies inthcdynsmicin'. cmphwir .n intmrtion and con. tinuour reoproul nuration; thr ids* thrt i t is the on-goioingco~plinybetwen environment. body, and nervous w e m that form the hrrir of ml-time adaptive re. t p o n t ~Aacrrplins both prlh dependme and rbc inanctiuc nrturc of buic srnaorimotor adaptation, b o w c r , r ~ i l falls l well chon ofcrtabuahingthe t h n k of n d t s l cmbdied cognition. Thus consider a traditional chi-that m romctimn solw pmblrmr by nploiting inncr madcis ,hat arc @ d sridl (by learning or nolution) to function u off-linennnd-insfor fcatvrnofourrcd-wrldmvironment. In ruchcurr, w t m porarily abandon !he rrr&t%y of dircclly intmaing with our world rc u tom. pp in more "viuriaur" f o m of cxplontion. I t is cchlinly po.rible that such oR.line pmblrm mlving is prrfmtly mntinuova with uariaw on-line, highly cnvironmenmlly intereccivc, motorcontml rlnegier. Thus G m I (IPPS) drrmber a pirsc of c i r ~ u i t ~who^ y p r i n t i d mle ir the fine-tuningofon-line rnchim~ Thc
nc
-
C.
REPRE5ENIAllON AN" COhlVLTATION, AGAIN
Anoth" wo", con.cm, the naturr lmntmt) oflny put.& intcmd q m . n t . sons. For i t lmlcr u i f the ergel of much d y m i d r t rlvptidrm is nor intnnd rcprncntation p r w w, much as r prticvlsr t p of i n t ~ r n rrprrmflfian, d vir. what rrr romctimes ultcd "abimiht' rorcunu~ion-the kind @hatmid, br f e a r u d in a drraild, vi-in,-indepndmt mod4 of mmc up& of the world. Nolice. thm. a wcond land Ibelieve, highlprignifinnfU a k , 199s) m y in which higher l w d cognition may bc ont ti nu our with is motor and dwclopmcn111r w l s . It may bcmntinuous insofar 8s ir involve inmmal rcprncntation~whcw contcnfs i u n l i h drmiid "objmivixt' rrprrwntationri nrc hcmrily w a r d towmed
CHAPTER 7
134
I
DYNAMICS
D. THE SPACE OF REASONS ofthe b n i n u l u * on? morefizd~, in the complr~OVC~II w h ofcausl influences In onr vnsr #hissobviously cmr. Inner and ousr faoon docon$p~rr tosupport many k~ndsofadrourrSUM"% But in another unu i t .%eitherhlu.or our wu:N .~~~~~ ~"irw d l have to change in same vcnldramatir & h i ~ " indmd For wedo 3uppac h a t i t is the mtaggaing rtmnural ramplexily m d vlrirbiliv of the brain that rre the key lo undenlanding the rpecifiully inldligence-baud route m cvolutionar( nu-. And we do suppose that that roue involves the ability, m u n w olmmplex neural rwnts, to k o m appraised of informorion mccmingau. rurroundin@. m d to uu that information as r guide to pmrcnt and future action. I f t h e .re not ""imr, t h q l r r vcrydov to bcingm. nut ar m n n ncmbrac. the notion nfihr hman i r ihr pnnriprl ullnfinhmat.nn-prweutnpan#nly,warcal. rndy seeing s as fundamentrllv dn7erenr *om, ca,. the flow of a rive! or the ae. t ~ n l r o l rolcanu. r A n J t h n ~ ~ n d ~ & r m r ~nl hea~ld ~ t o b e r d l r r c d m o u r w ~ m l ~ ~ mdpis: a difference chat rmicrlly is rcflrcld when wr pusur the kind of infarmrtion-prcesinpmdrl r w i n t d with compueuioml ippmarher, but the, look to bc Imt i f we t m t thc brain in n i a l y the umr t m r is. ray. the Watt govonor, or the bnling of a heart, or the unfolding of a bark rhnnicd r c n r t i ~ n . ~ The gunlion. in shon, b how to do iunire to the idea lhat rlmc is a prindp l d dirlinion bcrwrrn knowlcde-bad and m m l y p h p i a l - a w l wmr. I t d a not wcm likdy that thcdynamicinwill deny chat thrrc isadiffcrcncc (though hint, of snrh r arc somelimn to bc found). But rarhel than relponding by embracing a different voubulsry for the understandingand analpis of brain m t s rat lcart as lhcv m a i n to cosnitionl. the dvnamicia rmanr thc iuuc sr the " rxplmrtion ofdininnive kinds 01 brhaviord flrxibiliry and h o p to explain that flnihilit).uaingthc mysrmeapparattnr !hat works forolhnphy$icnl systrmssuch as rhc Wan governor. Such apparatus, howrm, may not k inninsicallynllsvitd to explaining thr pnicular way certain neural p m m s mntribua to khavionl flcribiiity Thlr i a
..
~.
Lnowldge,and other (oltcn highlycornplnl vyslrmr that do noldirplaysuehgoalo r i ~ n f bcha"io~? d The image of brain, body, and world u r single. drnvly cau-
p l d system threalmr to climinatc the idea o f purpa~ivcr g c n unlr. ~ it is mmbincd with romc m w i r i a n of d c rpci.1 m y gmlr m d knowledge S y r e in the origination ofrome ofour bodily motions." TkcomputationrVinfom~tion-pmcesingappmarh prwidnsvch rmognitian byrrnbrncinga kind ofdual-erpmrccount in which <main inner stares and prMeurr act a h e vehicle of h o w l d g e and information. Pcrhaps,thcn, what i s n r r d d i s r k h d o f d y n m i r romput.tio&minwhirh thr d.iailr ~ f t flaw h ~ information bit a imponan# a the dynrmiu, and in whichromclacal dynamic f a t u r n l e d a double life s d m a in in information-pmnring wonorny. Hem, then, is one way in vhich dynamic and computafiorul mnalyws may p r o d hand in hd." The dynrmic analyur may help identify the complcx and temporally extended phyriul p m c r u r that art as fhc whirlnof rcpmcnfafional content. Traditionaloxnputationalismmay have k n just loo narrow m i n d d in its virion of the likely syntactic form of the inn" bcircn of information m d contmr our k i n a t i o n v l l h the netic ~haracarrm d lttingr of natural lmguage Idus 10npdsimple. 1-1, ipltially encndd a l l t a to function as i n n n content beams. Cannectionist aooroachm hclocd ur w. be. yand t h a t "ision, by identifying the mnant brarcn nr dirviburd p t t t m of tivity. Bur i t may t& the full firepower o f dynamic ~ t c m thlaty r to r m d r k and mmplol space of pouiblc content bcarcrs.
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E. C O G N l T M INCREMENTALISM: TltE BIG ISSUE
The wol* in lnificid life (Chapter 6 ) m d dynamic Thmr niwr in an cspridly a-IC form, r pvulc that wr have almdy touched on srvml time$. Ithink ifis wonhwhik howrvcr, to now make this puulc as explicit and pmminmr as pa. sibla.
The p d e is this: What, in general, is thc rrlation thc smtcgicr uwd to w,lvr b.ric pmblcmaaf perception m d action m d thov used to solve mare abnrsn or highs lrvcl problems?Cm the cap<* to solve more intuitlvcty "cgni. live" problems (such rr planning n m ynfs vaotian, thinking about rbacnt him&.and dnigning a particle accclmalorl bc undrrrtmd in nrrntidly the rm t r m as the a p c i t y to follow w& to cmrdinatc finger motions, to generate rhythmic itcpping. and w, on? cenainly, much of the r m r li*ralurc on "rmbodid cognition" wcmr mmmined to a notion that Iam d i n g " c q i t i w in. Crcmensliam." This i s h c idea that you do inded get full-blown. human c q n i lion by gradllrlly adding " k l l r and while" to basic (embadid. embedded) %rnt@n of xirang to the prcvns at hmd. is just rvch a Pinriplc 01continu.
I,
CHAmR7
138
.
I
DYNAMICS
7.3 Suwsted Radium
,
dm and v+amfm ~ I X ) Ihc ntgescd lormmkd &t. m d dab h m h i i d a n ~ t i r nDF, t lor armplc. suRm f m m *ntnl mum l a ~ o o a m u IIYIONI vi-
(nan system f o r r i dlxpmsr
b
dyidcn~objc~ror*i$uaUydi~crimilutc ahapr Nonrthdnsrhcilrbk to pick u p theevery urn= a b w t h a t ahcunmt n n r r l l y d w -ije n'ifn git flucnt.nU-oticntd pmiaion&ripr ~ , b y c o n r m r , r v H r r d a r s r lstream , ,i,l -4 *hare linlc trouble s d n g 1i.e.. i d m t i M n g nhjm in r -d -4 but a lot of tmublc for 0b$8 they ran xc. I t is u thauEh they csnnot uu UK spatial information i n h m t i n my uirunl srmc' (Guuniga, 1998, p. 1091.
h r ormcibl< i n d d n s ro d y n a m h l ~ r nrkov, ' lly R. Abrnham and C. Shar, h. narn;-m< m m d v o f & h m ' o r i M d .Ch: Addiron W n I I 5 9 2 ) ; the dlpltr by A Norton. "Dpsmie: M infrodwlion." I n R. P o n m d T, n n elk l(rdr.1, M!"dosMo. tion IGmbridv, M n MIT Pr-. 1995); or (pnhpbn of dl for philarophen and qniliw ~ h n l i n sCl h r p a r 1-3 dl.A. Emn Kda, Q m o d Panemi- I*r *IT-~lliZaZkM 0fB.d. and Bfhamr (Ombtidge, MA: MTr ?,en. IWS.Chnpmm5 1-31, which also m n mi"$ dmriptlon, of h e wrt an ,hylh"i<,i~ogrr motion. For ihr work on mnfanr ritppnk see t Thelm and L. Smith. A D l n n m C S W 3 A P p m & re thr hrdqmznr ofCogninon andAmo2r (Ombndgr, MA MIT,rP 1594).md rntid&uuuiunin~Cbrk,"Th~dynami~al rhallengc." C o p i t i n S o n n 2 1 1 0 . 4 6 1 4 1 . 1997. ~a the wan -or naunnnt. w. T,n n Cdddrr. 'What mi$, mylition be if not
~
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.....
Same
, btiu-orim,"I
.
..
paper by R Be,. "Compu,rtioml-dpam~* ianglugn for .u,onamolu
ape." For f""hcrdiuu.rb" of ,he hrmd no,:on of w M r in-mmtinna. I. Wm. b Crinrnl Ondtrim, IGmbridse, MA MTr Rm. 1 9 8 . Chapter 17, pp. 203-2141.
at 10mn e r p l o ~and cmpt. more pnm,r,v. r n t c m l (For ccmc k w m 2 l l n g c o n l e
tun about the pmr~blcshapcof such sn inarpla).
Y I Uamaeo. :YW1 I n .um -~~ ,rr mvr!trrat ,Ilc J u c t r , n e o f ~ ~ n ~ ttn-ntal~rm ne wnfh~ml
~
...
u n d m w n d mindfulnns itsclf is still
unknown.
3.
To dcpin much d r d n n r d mgulan
,n the opention of the u d for on.linc. h p t m rapon*. hut lurid and rp~ h r to d ihc m t d doman uf p l n n a l andmr anafidol rosn8tirz u u l - l l ~ do-
b a r bndr of apariv
COGN ITlVE TECH NOLOGY Beyond the Naked Brain
I,l*ahr
8.1 Sketches R"""LmC adit* land a
,,,,,,
-,
W e have comer long way. Fmm the mind Image
ofthe mmd u a symbol-rmnchrngmealmachma to the delights of vmor coding m d aubrymbolir rnilicid inalligcnce, an to the burgconing complexities of red-world, rral-time intrradiw trms. As the iovmrv wntinue3.a hlur k m c cvn more pressing how to relate the inaighu horn rcccnt work in mbolia, rnificial life, and the study of situated cognition to #hebnds ~fcapacifym d iniviry a s o r i s d with l a - u u d high" c w i rion?How, in &an, to link the rrudy of 'embodid, enviranmmslly embcddrd' cognition to thr phmcmena of s b n n n Bought. advance planning, hyplhnicll
.
.
v-
mn.slordclikrarion,mdsoo~karad~rdsrompingg~~~nd~~fmo~rlrr3t.l
rppmchct. I n rrclvng such a link, there ur two immcdirtc options:
I.To embracer deeply h+rid v i m of thr inner compuntiond cnginr itrelf. To dcpin the b n i n rr the locus both of quick, d'hy "on line," mvimnmcnt.expk-iringnratcgia a d o f r varieyofmwcrpnbolir i n n n m o d t l r ~ K o r d i r y n "*is of "OK-line" realan.
2.
To bet on the haaic 'bag-of-tricks"
lvnd d r t n t w 011 the w y up-to st tho mehmi$msofadvance3 msan ra dee& continuous (nor a l l y nor archit=t v m and f n t u r n l with the Wnds of m d r n i s m l (of dynamic coupling, err1 xouted in L c Ian tw chaptcm
1n thir fine1 rcmon. Iinvestigatea third option-c p r h a p i t is rcllh jvrt a subtly morphd rombilution ofthe nro pmiour options.
It hdp. at lhir point, to ahandon aU pretence a unbiawd diwwion. For UK in+erwin thcrdationl !xmwa~mind and r m i t i v c mhnalogylies q w n l y n the h p r t 01 my own current m n d pmgnm;raling its cue hom ~ ~ n n 11995. cn 19%). Hutchins 11995). Kirrh and Msglia (1991). m d athrra. 7hc crnUII i d n b Uur mindfulnfuln, or nth., the w i d kindofmindfula-in4 with the dirrinaive, top-level achiorrmrntrdthr human .peck%=rim at ihCplodvrtivrmllirronpinnofmultiple fadonand force-me bodily, vlmr neural. some irchnolob5d. and wmc w r h l and altual. As r mull, the Pmiea dundrmanding whrtLdininnive about human thought and masan m a y i r p n d on a much broad" f a r than thrt to which mgniiivc xicncc h k o m r mart r c n n r a d . onc that inrlvdrs not just bod", bnin. and the asturd world, but Ur pm~~ndai&(pr.pnpc~s.PCs.irtiru~ionsl inwhirh our biolagirnlbnirulnm, mlurc, m d o p t c . A short anecdoteh l p r xt the mgc. &add" the q e r t b e n d e r . Faced nilh multipl~ drink ordrn in a noiv snd c r m d d environment, the expm mix- nnd dirprnw. dnnlv with amazing ddll a d rccmry. Bur what is the bark of this exmrformmcc? Dar i t all stem hom fmeh l v n d mrmarvand motor skills?Bv no memr. In mntmllcd psychological npnmrnrs mmpring novice and rxprt bmendcn (Beach. 1988. cited in Kid& 159%.p. 7071. it brsmcs d n r that trpcn skill invoker r delicafc interplay brwm inurrml a d cnvironmmul facton Thr exw l m nnd rmy dimnoivrly r b p d gla the rime of ordering. Thry then uu $hexpmirrrm c u e so u to help recall and -urnthe specific orders. E-rt prformancc thus plummelr in tetr involving uniform glluwarr, whrrnr novice pnfornunrrs arc unrffcdd by any such mmipul&tiar. The crpan h u lnrncd to rculpr a d nploit the wo*ingennmnmmt in mp that tmnrform a d rim~lif" the urt ,hat mnfmntr the biolaeical h n h . Portions of the m r m d world thus oftm function u ri kind of mnnold m m o q aarc. We may delihenlely lnvc r film on our d u k to remind ur to ukc i t for dcvcloping Or nmay write r note 'dewlap film" on p.pcr and leave that on our desk in.tad. & vrcnaf uordrtnd dm& wcomrmnd an n p r i d W & p and potrnt m a s of off-loading dam nnd idcar fmm the hiologiol b n i n onto r varicly o f m c m d media. Thir tric*. Ithin*, is not to br undmnimnd. For it affelts no! )us4 fllr gumtiq ot dala at our
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CHAWER 8
142
COCNITIM TECHNOLOGY
Take, for armplc, the process of w i t h g m x r d m i c pspr. You work long and h a d m d atdapcnd you are happy. k i n g r g c d phyrkdin. you assume that a11 the credit for the final insllrclud producl bclongfo your brain: I h c r r t of hum m reason. But you arc toa generous by hr. For what m l l y happned wu (perhrps) man lik this. The brain auppaned aomc mmding or dd tm*,mreials, and note. While rereading thac, it rnpondcd by generating a k bgncnlery idear and niticisms. T h e ideas and critisirm m e then stored at more mark an pw,In mrrynr..,n.u,nyu,n .I,r,r.rt. lllrlrr.,l, ,,,c,, yl.,nlr role,,, rmrynuongrhcw daa on'lnn rhmr.addlngnn nn-lnnc rcsr88nn. 2nd rdns. The 7 rlcofrod~n.." remondmaand m m a l rromotrahon 8s rmeatd.zeam and acatn. .. FmsUy. thcrc is r pmdun. A story, srgumcnt. or thmry. But this intrlletusl product o w e r lot to t h m rcpaad Imps out into h e envimnmmt. Crcdir k l o n g to ~ h rmbodicd, c embedded rgmf in the world. T h e & biological brain il just r pnlalkitarmtialmdsprcidpml ofarpatiallymd tmporallymendcdpr~ar. involving iou of mraneunl opmtionl, ~ h o ~ c j o i arlian nt creates fhc i l d l ~ t u d pmducl. There is thus a -11 m s e lor ro Iwould argue) in which the notion of the "problem-wiving engine" ir w i l y !he notion of the vhsk rabmdk (reBox 8.1): the breinmd body oprra!ingmthin sn cnnronmmtel w i n g . One way to undmtand the cognilivc mlc of m y of our wltmaled cogni. live twhnologics is aa rompbmtoryapmfinns 10 ,how @hatcome nrrorally to biologicalbrains. Thus mall the connrslionist imngc of biological brains rr pannn.compl~ing cnginn (Ulplb 4). Such dNlcn are rdcpt at linking p c t ~ mof r -nc pnsory input with a w c i a t d information: you hear the firs< bars of the song and rxaU the mrt, you ace the rat's tail i n d conjure the image of the rat. Computa~ionrlengines of that b r a d clru pmve ritrcmely p o d 1larks such umrorimotor mordination. face recqnilion, vaiccnragnition, ere. But they are not well suit4 to deduriive logic, planning, and the wic.1 t u h afwpucntirl mron (see C h a p t ~ rI~m d 21. They arc, roughly rpcrking. 'Goad 11 Frisbee, Bad st hi?- comiti". orofilc that i, a, o n e familiar and dim: f.mililr, k u w hum n int~UIgencc dcmly hss something offhat flavor; alien, because rr repilwdly rrmxend thee limilr. planning vacations. solving compkr ~qucntialproblmr.
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"
.
.
*..,.
One p
o d h w i , which 1 first encountered in McUcllmd. Rumcl-
hm.Smolen*y,and
Hintan 09861, isthrtrrtrnn.und thnr limia, in I q e p n , by combiningthcintrrnal opmtion of a mnnectionbt,pattern-complctingdNla n t h r n n o v ol r i t r r n d O~CDIIYIII doad 1-1' than w v e TO r d u m !he compbx. ? r g ~ r n !problons ~~l to an ordcrcd in a i r ~ m p l npanrm-mmplninpopnatiomof the kmd our hnmm arc m a t ~ o m f o n ~ hnl tr h Thur la l l c a'laumi rllu%tnlton. we rnev racklc the omblon of Ion. muit~olm~man bv . u m a pn, wwr. . . and nuwe then mge. 2" s p m n r of nrm.ls*mhnl manipvlsinn. m.riCa1 and norage so rr to reduce the complex problem to a sequence of 6imple panerncompleiting r l r p thal we d r n d y command, first rnultiplfing 9 by 7 and storing the result on p r p t . then 9 by 6. m d ro on.
"
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..
coder, by
. ,,....., .... d dog, tbc h
,
.
wirnming
.
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lar, canrider the b l h nm* Ilu tunsk p r d o r i a l l y tnkand P h p j d exmination mgyluitshodd sot b.~bl~tosrhirrethcaquatic fats ofwhlhirh i t ir dmoomrhiyopablc. It ir phyaiully tar ml. (by about a h a o r of 7) ro awim u hn rr it d m , to turn 1%
. .
Thc mlur of the u u of pm, paw, and n u m k v b l s is i h w that-in words of Ed Hutchins. a cognitive anthrop~logirt-
rhr
.uh lonl~lp r m d ihr lv-1 in dn the usL. that nnd to b r d a w h C &#.stk pp1e.w g d Omd? wognl,.ng pttern,. nndclcq~8mpred d d d d d d I l r mrlal. ard rnan,pvlalong ohjrn. ~n t h r mn#smmml IHul~htmI%<. 1551 """<~'l"
A mommtr M e a i o n will r 4 that this dedprion nicely caphrrs whst is h n rbutgwdcxnmpler ofmgnitive technolow recent w o r d - p m ~ i n g p c l * ~ web browwrs.mouw indiransystmvzctc. It r l w suggrs~s,afcoum,what iswmng vith msnyofourfirrtattonptsrf cmtingtuch loai.--thcrWlr n d d m w e h m . environments (early VCR's, xord.proc.rror$ e ~MR ~ prn.+those l thal biological brains find hardnr to support, such aa the mcali and orrmtion of long osmIiaily arbitrary, wqurncs ofopecations. Zcc Norman 115991 for diruuion. I t is rimilarly fnlilhl. Ihrlirvr, fa think ofthr praniccafusingmrdsmd linguiaic ihbelr ar itselfa kind of original "~0gnili"o rcchnolagyn-a potent add-on lo our biolouul brain i h n literally transformed the spare of human mn -. wc n n d earlier ihc obnovl Ibvt ail1 powrrful and impanant) rolc of mitten in-
COGNITIVE TECHNOLOGY
CHAPrER 8
844
wription. as both r form o f m e d m o r y m d m urna for new kinds of manipdrtivc *ctivi,y But the my p-cc of word, ~bjnh u.I.Ibrlirrc. some lunhcr, and gnnrUy 4 M e d (though we h n m . 1994. I%), ~onuqumcer. A word, then, on this funher dimmsion. Words a n a. rr potcnt 61tm on thc xalrh space for a biologics1 krming device. The idea, to s l i n t rppra*mrtion, is that learning to snocilte mncvts with diurcte rrbitmyhbdr (words) make i t arin to u x t h e concepts to constrrin future s a x h a d hen- mablm the requisition of r prapsriv. u u d c of moremmplnmdin~muinglyab~u.didcu. Theclaim (rc.&oCL.rkardThomton. I9971ir, othcwix put, that auocirting 8 p r a p t w l l y simple, sable, tnmd
*
.. .
itcmlsurhuawordlwithanidn.mn~ca.or oimcofhowlcdzecffcdrrtrhcna .
thekncrptintoamnofcognitiv. buildingblo&-anitmthi~can t h r n 6 t r n t d ar r simple &line feature for future epiroda d thought, learning, and wrrch. Thir bmsd conj-m (who= statistical mnd rompvtstional foundations are in O ~ ~ t r n d T h o m t o n 1997) . senstateruppond byaomc m r n t work on =himp cognition. Th~mpron.Odm. and Boyron (in pr-I n u d i d problrm i n ~ h i m p r( p n tmglodyrrl. What Thornpan cr d. show is that chimp trained to uw an arbitmy plutir marker (a yeUox triangle. "71 to d e r i p l e pain of identi4 objmu (such ar two identical cups), m d to u x r diffcrcnt markn la red circle. say) to designate pairs of different objects (mrh rr a rhm and a cup), .re ,hen able lo l n r n to solve r nor =la% of .bnnn aroblrm.. Thir is the clarr of problcm9intncmble to chimp nor provide3 with the v b o l i c m i n i n e involving rxognition of higher order nh8ionr of r m e n a r and diffmce. Thlu prnrntrd with rm, (difftrrnt) pairs of idcntiul i r r m (two r h a r and t*.u cup& r y ] the highrr ordcr w k ir to judge the pain as dihibiting ulc s m r rclltion, ia., to judge that p u hare rm innme$ of mmmrrr. Eumpla of such higher order judgmenu (which even human subjectsun lind hard to mrrnr at fiml are shwm in Tablr 8.1.
TABLC %n
--
Higher Order Sammsr and DiRnnc.
C"PlWI
-EusISh.
cup*
-.
A-p*. 1 r o h m o C 6 n r 4 unrm
o"hn,wedhi*&-
CuePk. w innmce,o(6J"&mm<e .n inof highnordnm-
EuslC"l ~p
,",lm..dBm~*~-~.nd.nd.ndd~&--
.niwrrdwmodn d i R m
The token-tnincd ch~mps'rucm..t thiid~flkultusk. ilir m n ~ m u dis, r i platncd bv thnr twncncr n t h m m . 1 token& For su~hrxpcnmzxc may m=blc ~ h cc h ~ mon ~ .mnlroncinn. r e . the oar, of anrnnul ruaa..to m t n m 2 mrnt.1 mracntatiaa of ulc ylmenm token (rr i t hnpm r ylllmr uimglc). F a p u r r to thcfwo i d m t i d shm will Wlorixclvrcrctti.vs1 o f h a t token. At thot point, the higher ordn r u k is eff=tivcly rcdvccd to th. simple, l o n r ordo W k of identi+ inp the two ~ U o plastic w tokens rr "the same.' Exprimrcwilh cxrmsl regs and labels thus m a b k th brain iadf--by repnrmtindthmc tags m d labels-to wlvc pmblcma whow lrvcl o f m m p l c r i ~ ad. ~bnranion wmld otherwire lkavc us bnffldinmitivc rndt whox widespread applicability to human rcavln is incrmingly mident (see Box 8.21. kerning r m oftags m d lab& (whichwedl do when we l n r n r l m y a g ) ir, we may t h u s ~ p c ulate, nthcr rloaclr alun go acauirins " a nor oercorual modalih. or lkkr r onccptual mmlaliry, i t rendor renoin fraturcsof our world concrete m d d i m & m d rllovr w to urga our thou&u (and lnrningdgrithmr) on a n w domain ofbasir ab*. This n n domain compres= what wcrr previously m m p l u m d unruly xnsoy p s t t ~ m int~rimpleobjms.Thrvrimpl~abj~ctr on then k a t r r n d d m in mp thar quickly m c d hnnhcr (othcmiu hiddm) patterns as m the caw of nlrtianr h e n rrlmonr. And of m u m the whole p m n . decph, iterative w t coin nor w a d and lakls to con~mir.q u l a r i t i n that m could only arigi"dl" ~ o n < m d i u u r ,null of a brd;droo of other word, and hbck Ihc mart powerful &d familiar inurnation of this it;ntivc antcgl ir perhap, thc dificr of human xicnrc iuclf. The rupcnrrrion of biob@l bninr with llglllfarm rmurm m y rLo r h d light on another parrrful m d charancrinie rrpnt of human thoughl an as. pea mentioned briefly in the intmduction but thm abnndond thmvghavt the r u b q v r n t diwusion. Ihrvc in mind our ability to mgage in xcond-order disrourx. to thank ahour (md mluatr>our o m thoughts i>u,
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CHAPTER 8
146
COGNITIVE TECHNOLOGY
.. . . SunLIrt Dthvm ud c d l q u m mdducc a paMful t+ o f widfor a s i m i k clum in the m*thrmatid dam&. B i d W hnins t h r i rumd'iplplry m & -, hut f u ~ m y d l o w - l m l numerical m m m a capcity
-
wnpl. " ~ r n . ~ ~ i t (I-ocrr, , 2."as, 3."lsa), m appredation o f 'marr:.IRJ."andof change inquurntity.But human mlhmticalthought. thq dcpmds on 1 delicate inlcrplay bm*=n thii innate V I r m fer Iow.gad+ appmrimm arithmetic and ih.o m dhd toak provided by the dcvclopmentofimgpwbucd rrprcrcntation. of numben n e d-Iopmmt of such n m twh began, they argue, with the w of body p m ar n a n d - h for the b U i numerical ~ qunntitis, a d ~3 pmgusively mended
t o rep-",
precis b m < e qrc*nhtion. More m n m l y , Dchvns S p l
XY. l a d Trkkio (1999) kp"dc"t on the
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I
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--
.*
wnted inmnauy, ssthepmcsr rcauiu imas.af l h c m n n s l iems lor later uw. Thhirsimdar to rhnoryabout thcchimp judgmcnlrnbout higher ordm rclarionr, but qoitc unlitr the C~SIof de~chimgthat 1 conmidcr
f c c t i w l y t h i n k i n g a b o b o t ~ i f h ~ r o ~ r ~ c ~ g n i t i u ~ ~ m f i l n o r a thoughrr. bouts~fic This "thinking about thinking" is a good candidate for s distinaixk human upaci-ne not cvidrntly s h a d by the other non-Impage-wing a n i d 3 who share our p l m e ~ As such, it is n a t v d to wondn whcthcr this might be m mum SPK~Oof thoughb in which language p l r p the genmtivr ralc, that is not jun nn x a d in, or a t a n d d by. our u u of words but is d i m l y dcpcndcnl on language for its v c y ainmce. I t h nay to ul, in b m d ourline, haw this mi*, came about. For a8 mss wcfomulircs thought in words (or an p a p ) , i t bcmma m objm for b01h ourrclvn and for othen. As an objm. i t ir the kind of thing we ran hsvc thoughrr about. I"
dnurma rc plrslblv ucn u onr mot of the ~ c n t ~ h l c e r p l a ~ ovrnnon nof o'extnnrl inhnologrd urllold~ngin h u m " cul tvnal nolvloon 11%. bxausr w c u n fhlnk about 02, u r n ito.nLnn~lhal Y C L a(~ " thrly srrunux our world in mp design4 to pmmotc, support, m d a t m d our own cqnitive erhiwemmu Thk p m c a d m fee& itself, as when tlw arrival of m i n r n en and notation allowed us to begin to fin mr more mmplcx and atended srqvcncc, of thought m d -.on a* 0bjrctr far huther wrvtiny and m"<"pcnrc of luch urond.ordcn <-nus*
ti"".
As a final example of cognitive technology I w i d w m ) in sabn, IN ur Nm away fmm the rae orwords and tm a d symbol-mmipulatingtar18 ( P a U r l rnd ~0Diderthe m1. of skelrhimg in cmain pr0Ces.s or rninic creation. n n Lccurm, Vcntijnen, and H c k n (1999, p. 180) offera u r d u l rcmuntoftlw rreation of rbstraa art, dcpining il sr heavily drpcndcnt on "an intenniw pof imgining. skeching m d walurting l l h m rrskcfching, d u r t i n g , dr.1." Tho quation the authors purruc ir, why the n d 80 sketch?Why not rimply i m b b the final amrork 'in ihc mind's eye" and rhrn execute i t dirmly on the cmw? Thcrnswccthy dmelop, in g m t d c n i l m d ~ ~ i ~ g m u l t ireal p l cu w sNdin, i s that hvmrn thought is constrained. in menu1 imagy, in wmr u r y ipccific vmp io which it is nor r o n n n i n d during on-line preption. I n particular, our menul imrgm rmn to be morc intnpmriwly fixrd; Ivu enablingofthc d'iovcryof nwd forms m d mmponenn. Suggrstiw cvidrnrr for such constninu inrlud" the intrimin. demonrmrion Icbamben and ~ c i a k"r e( 1 9 8 5 h r r Box 8.31 thrt i t b much h v d n to diwovcr the vcond i~~terpntation of m ambiguous figure in rcu u and imaginationthan when ronfmntcd with a ma1dnxlng. It is qui* ~ yby . contrast, to compaw irnagincdclcmmu info novclw h o l b f o r cuimplc, to i m g -
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CHAPTERS
/ COCNITIVETECHNOLdGI on dirrindvc f e a ~ r u d t h ehuman b n i n (orperhap~thhuman b n i n adbody; r r u l l the o n c t p o p u l ~ *orin about tool us m d the nwouhlr thumb). Lrt us be dar, then. ,ha the mnjmurc scouted in the prncnt chapter is not mnnt u 8 denial of the nirtmcc of cenain a d d ncunl rndlor bodily diffcrmrcs. Rathrr, my goal is to drpid m y auch di&mnces s the d, rather !ham the full explrnm~ lion, ofovr cognttive capabilitin. The i d n L that some rclatixly rnaU m u n l lor n m W i l y ) diffcrmcr msthe sparkthat lit a kind of intellmud f d Fnr. Thr bnin ir, Id ur arumc. whollr rrsoansiblc fcoune~. ..,o.rhros of somr ouitc small wnX of ihc mgwetingl for rhc Nulfilmmt of some prrcondition of cvltval and Irchnologi~d mlution. Thus k c o n I15971argue that human b n i n r caunev o f r disproponionar ~ n l . . ~ = of ~ our ~ t pmfmnl.1 loh.~rclativc to the rrs, of our brains. arc uniquely able to learn rich and flexible whcmu w i a t i n g at4itrary qmbol. with meanings. Thir thm, L ooc contender for the neural diffcmncc that m k c r human l a n p g c acquisition pasibC and language (of that +) i s quit< plausibly,the fundamental "copitiur trchnologf ithe UR-tcchnalogy) that got the whole ball rolling, There i r e many altrmsivr explanations Ian ~ ~ p r i a linly frmtineonc. Ithink. is to be found in Fodor fI59Ili.' . .. But the m i n t is that once thc prwas of ~ulturnland ahnological ~ a l u f i o nis under way, rhr explanstion of our concernpony hum- r
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Pme-3
A i m p * eumple of ihkind of multi!q-d smctuw i m d in -*.in *p. ofr!xlrxlarC I R r p m d ~ d h m n n h u m na1. (1999) WHnd pmirrionofdwru. ~horsand the publsl.h.r, Unirrrriq P m olhmmo.1
The conjrnurc, thm, b that 0°C l a w jvmp or diiwontinuiv in human mgnitbe ~ o l u t i o ninvolm the distinctive w y human brains -Idly one and exploit i*id.u.-nrious r ~ i ofncogmiti*. technology ablc m expand end rerhapthcrprccof hum- resaon. Wc,morech.n anyorh"axsturr on ihc plrnn, deploy nonbiologid widware ( i n s m m u , media, notations) to mmplmmrour bvic biological mods o f promsing, crnting m d e d cognitive n(rtcms whorc camputaciand m d problm-solving promn am quim diffcrcnt hom thow of rhc naked bra,".
82 Dircvui~n A. m E PAWX
OF
~ c n wS W P I D ~ (AND A m a r r n * w~ ~~r ~m~o ~ )
The mrm obuiaus problm, far any attempt to nplain our d a i n c t i n mmur b y a p p d m a kind of qmbiorir of b n i n and r~hnology,lies in the thrcat of cir~ l d y Surrly, . fhr m m y 8% only inttinriully m n brains muld have the know1ed~cmdwherrwith.l t o c t t such rognilivc r~hnologirs in the fin place. AU ha widovare unnor come fmm nawhrrc. Thir is what Irhdl dlthe "paradox of rnive nupidiy.*
$0on.
a his idea of r potent aumarion of cognitive technologin i. n ~ i a l y ~ g g ~ . five. Ib d i m , when combined with h c Inill-hlive) nrnro%ienti% perrpclive known rr ncvral rontrunivirm. The mud .lrantrvdivirt ( a m Bar 8.41 st-I the rolcof dmlopmcntll p h i + in rllawing the human mna lo nnivcly build m d rlmnurr itwlf in roponw to amironmrnt.1 inputs. One poaiblc ruull of such r p r a n s is to magnify an .Red Inll "rognitiv. dovetailing," I n cogni~ivc domailing. n m l murccs k o m c m o u d w rr lo fartar rclishlr m m l r r wurces and operations into the vety h a n d their problem.wlving m u t i n n I n this way, the inncr and outer r ~ v r come m to romplcment nch othn's op.ralions, wr that the huo fit togcthcr as tightly u the r i d e of r prccidy dovetailed joint. Thus thimk, for cumplr, of theway thcskllled hincnder l x e t a t ) combined biilopiol reail and the ~ h n i namncmcnt l " o f differin. s h a d dasrr to roivc the cocktail bar problem, or the wry the tuna (Bm 8.1) swims by creating quatic
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CHAPTER 8
'I'
NEURAL
cM;NInVL TECHNOLOCI
CONSTRUCTIVISM
,.
.. . . . ',:.; ?+ . . : . :i m ~ l h r ~ c ~ t d e p i c a d ~ ~ m r t i c l l ) p ~ i rim-dmt, and u involving the srtd m a r u m a n of new n m n l ~ircuim(( ~ ~ r , ~mom, p u *dendrites) nthcr ih.n jvrt thc be-Nningof tirmitry w hw tmic $hapm d form arc rlr& &&ned. mvlr is that the learningd c k i n r l f r h e n ~as a r n d t d ~ m b m m v i r a n m m inn~ ,
~
tnrctiodaclnincdocr oaf iurtallcrtheI;nowkdwkdwkdbab..i~dtt themmm ~~-~ " " . puutiolul architermre iwlt Evidence for thc neural e o m n m i v k t vim mmer prim* from -at nmro-tific nudie ( s p r a d y work in &vrlopmmralc~tirrncuradmcc). Krys~udierimludrworLinmIvingmmlid t r s l u p h s in which chunk of v i r d
wfi
mnicu thsu it rhcn qloita. Now pictvrethc young bnin. Inming tosolve pmh1in la ravimnnxnt with p n , ppn. P C .a. That brain may dmlop pmbbm-solvingnntqies that factor in thrsr pmp just as the hrtendrr'r brain finotorrinthc~v~il=biliryofdiffmntlyshrped @rumtoreduccmrmarylord.What this s u ~ g n fin~the rather rpccid cent<* of the wnl i-onnruaivin's l w r Box 8.4) drvrlopmentll w h m , is that young brains m*y m n d-lop r kind of
m.
ir true. it t not jwt that basic biologicalbniru cm achim morr and mmo as the tuhnologial runound evolve. I t is that thc biologicnlbrain l i a d l y vowr mrr i a l rognirivc a r c h i t d m suit4 to ihc ~ ~ iirrhnalogiul f i ~ mvironmrnl in whieh it I c a m m d mrrum. This lymbioli~of brain m d rognitivetrchnology, reagain and *-in, but *nth ncv technologis wulpring new hnins in differmt mp, may be thc origin of r golden Imp, a vimaus spiral of brainlmlture inflmmmrr lhrl.11"hllmrn minds to 90 " h e n" animal minds ha". Eon. hcfore.
Some will r r y c that t h m t nothing n w or ~ l p r i r i n g in tbe simple okmrion t b t brains plus thnology a n = < h i mmom thsn "naked brains." And cvm thc n d i o l "dmeuiling- image, in which bnins plus rrlisblr pmg mmc 10 an sr intrgrted prohlcm-rolviag enmnbla may seem to have for practical implktioru for the m p i t i ~ ~ e i c n l i f i cpmjm. what. thcn, is thecash nlue of lmtingthe hum m mind a r mmplex sptcm whose bounds are not t h w of skin md rkull? One nnaical. hut whoUr, nrutivc. imolicatian is that there u n k no s k k " " m i t i v c lml"(recall Chrpra 2) a which to pitch dl our invnrigationa,nor m y bound4 $ys!rm (such ar the bnin) to which w e o n r n l r i n our intercognitive rricntists =.king the narural mou ofthought and intclligcna). To understand the hancnde's skills, for example, w anno, restrict our attention to thr hanendcr'a brain; inatcad w m u l r u m d rothe pmblem.wrlvingmntribulionr of active cnvimnmcntal nrunuring. Nonerhclcs, it ir unmlinic to immpt-in ~ ~ " ~ " 1 -tlke t ~ ewyhing (brain, body, .nvir~nmCnf. anion) into rc
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CHAPTER 8
1%
COGNITIVE TECHNOLOCY
wh.a: to rrr that much ofwhat manm about hum*n.lml inalligencc b hiddm no, in the hnin, nor in the technology, hut in the
snd inanted inanclions m d roUabontions beween the nro. (Thc account of skcfching and inktic cmtion $9 e nicc eumple of the End of thing 1 have in mind: hut the armc 1-1 of intnartir. romplmiry chuncrnircr slmosr dl forms of ad\snced human cognitive rndcevor.1 The study of lhac interneion spa- i. not nry, and d r p d s bath on nm multidiiplinary r i l i r n m m d nnr forms o f m d d i q m d mrlyh. Thc pyoE hmrr.cr, could hr rp*tll
~~~~
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~cymtwuldbea~thsmonitonpuron-IincmdingWb w+kh n ~ g m v pp u f q r n t l y .ccau, err., or p u r on-line CD h u e
habitr,md thm wuchsoutoewilrnathrtfit your rppmr i m c m on:. aophiiutcd a h sgmu might monitor m.linc ru*n% bidding .ad wUmg oa your behalf, or buy m d ell yovr no& m d sh.m Rdkn on the posibilitia. Imagine &at you begin using dr ueb a 4 Dcdiarcd w h r e agnrb track m d d a p l to your merging in*& and' -domcrplantiolu.Theythcn M p d i r m p u r m m t i o n t o n r n k u r b ' ' : pm and p d u m Over the n m 70 lcrn p~a d PUT mftwe a p m . ' uc l d r d in a compla dm- of mrvalutionary m d larniog &''. lneucnrin& end k i n g lnnucrced by, the Mher. In swh a caw, in a n y d wow, the h r c m t i t i n look Inr likc pan of yoor pmhl-soI6ng a6 r ~ m n than t pm of you. Thc intclliwt w r m rhlt now mnfmna be. wider world !A biolagiral-you-plus-ththththh~geetdtd ma. cnm.1 h. dlca of mde ut connibtrbq rather Ulu ihc wiarv subpcnon.l +tim ' fvnrdanr d u e in yovr own bnin. They re r o n r b t k qt w o k mntrib ingm PUT cm+ngps)rholo&l profilr P&p. you fuldly w c o v o tb ing" t k w R w r r y e n s only in the umr anrnmtd m d uldmsteh. py.. doxial way d u t l.ou count w 'uing* yaw hip-pw or r m n *I~ Whereas dcdiotcd, -hind t a h r a o v r m are mending individvrl w i t i v r w r m a ouaide Ihc Idbovndr of sLm ~ n &dl, d wiar , , forms of biwlmmnic imphnt m rndy to tnnrform ihc m m p u u t i o d architemre fmm within Ihc biological &ir-b.girvU. Per+ bpt ayltans arc dnrdy the bm&inria of r a o n k ~&nol+e inm Ih h dircrt l i g e of imphntd r l m r o n i s to biologid news and Cahlcar implntr, row of which now b w the auditory mm md @& d i d " into the b n i n n m I= k V l y . 2Om). d d y help thedr4 do;primmul minrl i m p h a are now ready to .Rut amin clus of a d d blind"% such ir .gc-rclatcd mludrgmgmtioa ihc nm step in0," 7b a a fotwc m u 1 k to W such implrntrd d a m n i a -ore dirraly m the n d qrlinvolved in rcuan, r e d , m d imlginlti~n.Svch a rtrp L d m d y bong ukn. albeit in a crude md a d y arplonmry my, br
.j
SELF
One rather pmblcmatic a m , im thor ofur m n n e d m the kind ofmmded aylremr pinwc prrwntrd a h . con-7 Ulr notions of wlf m d ngmnq. G n it k literally truethat the phyaicllw r m whow vhirringr a d grindine constitute m). mind is n m t m that include 1x1 time) elements m d ormtionr that l a w our. side my phpicd lbiologidl body?Put dnmn!ully, am I r dumb agmt M i n g in r wry rman m d supportive world, or a sman agent who* bounds ur simply not thow of sun and skull?This h a topic that Ih m addnrwd e l m h m luc Clark m d Chalmcrs. 19981, m Ishall rcrtrid m ~ llof jurt a f w pints hm. W e a n &n by ~ ~ k#impiegualion. i ~ ~ a Why is itthst when w iuc Ifor example) a m n r to lift e hnvy night, we (properly1 do not count the < m e m inc m i n g our individual muvlc power, w h m r when we sit down to finc.tune an argument, wing, prpcr, pm. m d diagrams, we arc i..r prone to iarcr "hctor outm the omtributinnr of the ornos and toola and tcnd to see the i0tcll~u.l ~mduct the raults of our &on.? My own viw. u s~ggcrtdin the ml, h that u one dillcrcnce lies in the vay n-1 problem-solving proz-scs are thrmwlnr *d.ptcd to make dccp and ,-tcd uw of ihc cognitive widcwrc. Another lie. wrhaps, i n thc lwping and intmeivc nsturr of ihr inlenctionr thnnwlvn. The i r a n ~ d r i ~m e rd t h i c i n c n r h maker rdrivdy indrpmd~nt
-inr.di+"""khi8of~p. lk first, rlmdy h& but rq$dly g d r i i g in u b q u i ~ -hid. d ation is crrmplrficd by aaacd robe *stnu A simple oclmplc d
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CHAmR 8
116
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P
COtNlTlVf TECHNOLOGY
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M i s m w m r n n n m b kmdm* innrknn.amc b w d l n in
io un.inpmmseofmi&
htGo m iym l dzybep r~ tccd ormmptb m m u d by implanted wchnalc+s a u b l i w ro &Iol o w n a d wrhilitim on a Lind of x r m d q dispky, o p n i q the door to m LYCII m r e pawrhrl qmbimkbctwbctw b!+d u p y i t i e s m d the rnihmul (but n m intermhedl ruppon I n s h a . hwnm m i n d f i i s is. ,.a". w i n 8 mare m d mare m d and UI m of hc w i t i w machinc while ~ i m ~ l t a n ~ - ~ ~ lvvl lLvu,-ithi",
Lr
.
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fit, a d m a d p
prime hum,
-
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-
the rm) thc skctrhpsd opcnlionr to count u p n of the mbt's awn mental pmnarr lads ino~iublyto, e.g., counting the database of I c b ' , v l o p l i a Britanniro. which Ihin mv, earnee. c.uoan of mv, g"c n m l h o w l d ~ d .Such ~ . intu" itiveiy pcmkioua crfcnrion ( " ~ ~ p i t bloatel iw is not. however, inevitable. I f ir q u i t c p r w torestrid thcpropmd aids that a n count upn dmymmtdrnrchintry to those that arc, at the vay least, rcliably aniiablcwhrn ncedd and uud (ar
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~G=rt.rakindofmd..*-bm~ttomyamntioobcndp8.w. hadof O c a & d T h e n p ~ * t & W s h i ~ o n Unnmity Sdml dMdi c i . Blwn hmd bcm pvulrd by the opldry of v M i n AWuonn's ruffcrc s to live done in thr community, rminlsining I Lml ofindrpcodmr funrtinning quite out of step with their worm m atandzrd urn dnigncd to thcb u p c i t y to live indcpndnb. me pvulc w m o l d when h u m rad her
if
ppr md raffoldhg able to p w i d r -(ha the ncunl ddkimm mom might be I a M d , impatant ad* (bmk hob,ctc.1 I&in full &w no la lo be easily found when n d d "memay bmk' of fnames m d 6. tionr k v l cptmilabk, and mi% muuncs kg,bua to Dtnny'r a t 11LM. for hmch) reh@oualyadherd to. Such r w i t i v e scaffolding might be the w o k of ihc p l i m u rhrmulvq put ~ ~ d l a lin l yp k e u the b i o l ~ g i ad .-l .ran w o m t d , andlor M u~ by familv and hiend* Nm.rhcnfir.t ~onfrontrdxith such c l t m c rctiaouon m n a a l dfolding, it i$ empling to ur it u undnmring a hioccnnic vim of ibc individlul igent, rr d q l y p ~ h o l o g i u l l y compromied I~vhmifha-, that this tmputioo is r m t d not i n any d m facts *bout the iotrmallmrnd boundnry, but in n m h af unfvnilikty (thee are nor the ertemrl propthat m o n o f w uw) and inmffiricnv irhr mcmd propare w x n u y able to offset only r f w of the debilmting c R ~ c t sof Uu A l M r l . Thus consider. on= a&", the nht a d thc sktchpd. i n (hi ow w do not find a u d w lamenting the anin's tack of "MI" creativity jun bcom rhc rratirc p m a inwlvca m a t d and crrmtid ialmiadnof tkerch. ingmd qerceivink Nor do wr ndum our admiration for the pact, j u t be-
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cruwthr~me~n;onlyco~qofmud~lmttytcrivlr,dthpra m d pap,. To ur what Iam getting rr here, ima* nart thrr n d human bninr displayed the wid chnndenrtler of the Alzhdmo's b N n r Andimgin. that w h d r l o w 3 y n o l d r Iociery inwhichthe kn&ofpmps m d rcaffoldingdcplolrd by Raum's Alrhcimer'$ patienu m m the no*. Findy. rcflra thau 1 . 1 ir arcrly (in a r m w l what w have done ow PC* skclchpnds snd nar o m p l r m t our b.dr biolag*ll cqoitivc p m 61c i n much Be m e kind of my. Perhaps seeing the n m a l deep ma* 6ua trmbiab b M e n h u m brhinr and m m a l technolee wiU pmmpf YI to &iOk e ~ m idns c a h u wmt h irro have I cogmitiw6didh end to prsur, w t h inrrawd m e w . a +ion of fuU m d =nuin. w e t i * &. bJiUMn wing v u i o v forms of mpitivc sca8oldiog.
158
CHAPTER 8
COGNITIVE lECHNOLOCY
Thcrc ir alw a ma1&ngnofmingto theoppsite mmmc. Onre mind h looted firmly inridethe skull, anc i s rmptcd to ark whether m n Aner g n i n d localization might be i n d i u d . Thus cornidera *ior e r p r d by Hrhn Simoo. Simon saw, "cry dearly. that portions of the rmmd wodd often funrtiond w a nnnbiologiol Grid of memory. But inrlrad of counting thos podonr (ruhjm n, the pr&wr jua rehearsed) u pmp. p a of the knowing syslem. Simon chose to go ihr other my. Rqarding biologiol, on.boad memory, Simon invita ur lo *view chis i n f 0 r r n ~ t i ~ 3ncnnary ~ ~ ~ ~ra~less k 4r pm of the o w n i r m than of Ulr environment m which i t d q u " (Simon, 19112, p. 65). Pan of the pmblcm h m M doubt oridnato fmm Simon's o m l r oasivc imcre ston~el view of bioloaiul memo'y-wc now know that the old datnlp-r dirtindon offers p r ~ i o lifflc u~ I-rage when confrontinghiologiul rompuutiond sptcms. But the hepcr irruc. I s q m . mnccrnr the underlying image of wmelhing l i r 'con agent" rur. munded by (inrcmal and mtrnal)ruppon s ~ t c m r(memories, uc.). This ;mas ia inrompsuiblc with the mergn ig body of results from ronnenionism, ncumdmcc, aod artifitis1 life that we have t e n r&oringin fhr pan IN^ chapters. Instead of idencifylng intelligmcc with any kind of rpecial row pmus, thnc recmt invcnti@rionadrpinintdlgm<~ar anring hom thcoprndon of rnuttipl~,oftm quire swialLpumow murina, mme of which rriu-cma ncunl kdily and environmrntal boundaries and which often o p n t c wiUlin the bcncfits of any kind of $table, unique, cmlnlkd conrml. Simon's view make k t s e ~ against c the backdrop ofa pamivc vi- of manary m d r commimmt to romc kind ofccnt d i r d mginc of .real' rognilion. To whatwent wc .rr willing to abandon thcrc~omrnitmcnts,w shouldh ~ d i n g t o e m b n ctht c pouib'iliRofgcnuincr~ ,cmic."lmrion. in which cxt.rna1 pC0c.J~ and opera,ionr come to count n integral arpmr of individual human inrdligcnrc (* Box 11.6 for wmc fvnhn rantidcntionr1.
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..
-
for funher idas about he uu ~frnn.onnm#*rlnrvmrrr!o8 w n t biold-I cwiIbnifon, u.-idly E. ~utchihinr.G p ~ i o in n hr IY!AiGrnbtid8r,Mk MI? Preu 1%). fan. tvtiully rich and detrild roaunrofhow multiple mmnal ~ ~ n ~ w n i b uthe s pnrto of hap oaG,to in (it's.& ider,cddly.tomdCh*par 9olHuwUnr'bwkfinl). Danicl rx."rn hri don. pionetins mncepxp'ud work hemboas; Y I -idly D. a n o n mren'' mngnow r d a (Nnr York: Simon and %hun.r. ,595. Chapters I2 md 131 m d ~ . n n n r t t . - ~ ~ l u n g n i n p t o n i n k w i t h~.ll u p ~ r ~ 5 o f h i ~ ~ e l l c n t ~ i n & o i ~ i n d r ( ~ m Yark: Bast B W ~ 1 ,m1.For my own m"emps n bringingsimilar id-% into focus xc A. Clark. Bonx Therr(Cambridm. M11:MIT P l n r ,597. Chaptern 9 and 101.
c - p u ~n ~-nb $lnnnmon ( m b r i l g , ~ hMIT. PLPP,I p r a y thr -P by AgeraBnh Hernrmd u .I.. and Kinh. For much ma= on th-puibk &tions Lanm Iang*ae a d W r .rr Uw mk. lion by P. Orruthen m d I. Boluhn I&.).hnrind Thowht(Grnbrid~,Engad: Cunbtid~Univcmin, P ~ IW81,npullylht-p s by C~mihrrrand by hnnm. My p = ~ An Clark-Magic Words: How h g u r g e Augmmm Human Cornputanon," appus then rlw. For momon the lanp@@tho~~hllrulnr conMtim, Y C I . 8mm.AmdMum. ingimbrids. M* ~ a r n r d Uniwnin pr- ~m). For ihc in#<mlaybcmnn ~lraldidnmnn and the nwYr ofwhn-I i n m h ur D. anna!, ~ 8 - o d i~~ i n d sIN^ Yort: 6 - t BOOXI19%. chapten MI.M. ~ o n w Ori& of 1ht Modm, Mend 1Ombridgc. M* H-axd Un
C !1,
For a dif-r. diflculr h r m y mnhvhilc n*. on awh is* cr C. T+r, -H". Taylor Id.). P h i h p h i n i ~ p n r m (em b r i d ~M& , Haward Univedv P m % 1991). On the lopic ''qhor d m thr m i d nop m d thr mtoflhr d w~?'try h Clnr* indD. Chdrnrrr 7 h c m m d d m i n d . " l n n l ~58.7-19,11998. Nx,l. Hau@uxl.'Mind cmkdid and embedded.' In I.Haug&nd (4. Having Though, IOmbridgr. M& Harn r d U"l"~.,i~Prry lW8L For. ra* "ifid (,ndnrg.n"r>.ppull d,h.-aMdd mind" idra.srrK. Butler.In-IAfoinlDordmh~Thr Nlthrrlmdi: Uunr. 1598.&p-
b, 1hn~ua~r.d xolw." 1°C.
,..#, ... ..
1.>n~lly, lur 8 fully cowme mnnrmomw pmpox.labu84,lvlr 01wb&n b p l n " x k m a u wd vgunl8.l ihau@lpraon PDP nodrh' m I M.acUmd. D. Ru.mehm. md the PrlP ~ ~ r croup. < n ~rro!!,t rn,mbulal R M W * ~vat , tbm. b:idae. MA UIT P W , ~ ,986 7-58 I*
(NdRralk a) Condurhn
(NOT REALLY A) cONCLL~LBN
Firm condutisns ere out of place i n what wr m a t simply u r romevhmt &Ikn@g, divvnivr l i n k text. But t h e is on. modstly rrlirblc moral to be dmfrom our npid~firrtour. I t h t h r i h . h m mind. undmtmd as whatmr i t ir that svppnr m d explains our panem of flcribk. appropriate, m d (smclimn) ream-msitivc rrsponv, is r mnrtirurivrly lraky I t is a ~ t r that m raisll any single opprrn~hsuch u Uut of dsnicd L I . or cannctionum, that rninr m y single im( ofanalyrk, such as ihc 1rv.l of
~
16,
I s u l =a the creation of r b n m ~l dcpnd on thc mmplrx intoplay of n r v d o p n t h n r , bodily action% and thr uw of multipk aids, prop, m d mifans. What m think of a thc "mindfulness' that m a k intelligent khaviorpmriblr may t h u k b a t undrmmd u a produn of immenw and mulrifamrd lrrkage. A* an inlrinsirallr bound@vrrmringphmommon, mind prrwno m csprirlly diffificult o h j m of rtudymoving target. whax b a t descriptions and riplmstions simply -not, in prinCiplc be connructd by the ustofa single tml, p p l i v f or snabic mode. The w i ~ n l i l i r uf mind thus demands inter. diwiplinarl e f f m and m u l l i d i ~ p l i n r yc m p n r i a n on r whole n w u r l e , pmb. ing adaptive m p n w at multiple orgmintional lcvclr induding thosc i n m r p raring bodily. c u l t d . and cnnmnmmnl ulfolding. " ~ i n d w a mas s o h " That mr r gmd slogan once. But i t ha%served i l a pu-, and i t b time to mow on.
APPENDIX I
Some Backdrop Dualism, Behaviorism, Functionalism, and Beyond
When dualism m s in its heyday, amund thc time ofthc rmnteenth century. there were three m j o r contenden as an account of thi rrbtion: I.Parallcliarn
2. Epiphcnornmali~m
3. lntrractianism I . A~cod~ngmthcpmllrlbt.thcmindmdrhr hdyarrdrnannandau,slly irolamd Ncirher ,% capable of affming the ocher How. ~ h marc . n40 srmunl for the aoomroncr alrat8ul I8nka.r." . thr tmnrrwon w haw of * u h n a u l m s anton and blows to the herd ausinc hdludnaron, rmrrimm?Swtchmnimtion wr to hc the kv. God. or rome other force or rgmcy, had a"m@ ms,tcrJ w that the two owl ardcrs--the mental and the physid-would run along in harmony. t irwo i d d y accurate docks ut to the ram* initial time and I&to run for ncrniry, ndthcr suseining or conruhing ihc othcr, but thr two in prfm ascord noncthclrrr. The ,mvbl,uith par.llrlism iswho yl thcdalu? And why.ifit mr Gobdid Cod rcmn to such a clumsy pirrc of 2. Epiphmommnlirmis like pralklirm in w m i n g t h r cayul isolation of the physicalfmm the mental. But it mlaxcr ihcrcquircmcnt in fhcothrr direction. Thc epiphcnomerulistallows that #hephysicalcm r a w the mcnnl, but denier that the mcnui can affect ihc physiul. The mind, on this account, is somewhat (though only romewha) like the exhaua fumes fram a o r . The fuma accompny and are caused by the activityof thc engine. But they do nor (~ypicailylp o w r the car. lun m, the cpiphrnomcnalia holds that hiidsand Ulaught m d 0th- mental npricnca asmmpny and arc aurcd by brain activity. Bur lhry do not r s r u s c~ a w the body to an. They arc just the icing an the cognitive akc This ir r counterintuitive prospen indeed: it certainly fielsir i f it h my desire for n Pcre's Wirkcd Ale that pmmptr the trek to the local hostelry. l n m f u rr the wholc impetus for sccounts that r n c m a rpcial place for mcncd phmomma comer from r desk lo rnpm the introrprlivc widcnce, this rcmr an odd condurion to luvo to a q t . 3. ~nmmanionirm is the molt immediately rppnling of ihc dualist p i t i o m . I t tram the rncnral and the physial i s dircincr bur aurally i n t w t e d items, thus aroidingsomc o f t h c m n ~ p h p i an lm d introsprtiw implrurib'dif).afparallrlismmdcpiphmammalirm.Thc most hmousfarm of intnactionism iscaner i m dualism. On D c w m d famous modrl, the mind is r totally nonphysiol subrtanc~that a ~ o thc n body by influencing thcpinnl gland ri the baw of the ne& The My. by the ~ m route, c influmn<sthe mind. ~~~~
..~~ ~~
The p-t
t e n bcginr quite rlow to w h m man philaophiol trnlmcnm end: ~
.... ~ . . ~ . ~ ~ ~
~
cognitive pry~hologl,m d miiicial inteliigcnce. In l h r n brief notes' Ioffer rome roudwmd-rcadvb a k o u n d . in the form of a for amem ofn fwhinoridlvim-
When m inmpcct, or nRcn w our o m thaughtr. felinlingl. m d hclirfr, we do nor flnd anyhing much like phylial ohjeds. Bcliclr may be i m p n m l or trivial. f e l i n e mong or wnk, but not literally big, or colored, or heavy, and w on. On the . .... m . d e n u nf .. inrmr-tion alone. then., w minht he inclined to roncludc rh8 the mind i s romuhingquitr rcpantc horn, and dqlydirtinct horn. the physical world. This acfmlv natural vimooinl ir h o r n ar dunlirm. a n t i d t d a r r philorophid theoryofthr nalurcof mind. Dlulirrn h some whet uninformative. It lclir us what the mind is nol: it ir not r normal physical item ske 1 body. bnin, tablr, or chair. But i t is .mbm"%singly silent about what it might .nually k But atill. knowing that the moon il nor made of g r ~ chn it quitc handy. even i f you do not know what it is aclully made of innad. 50 leu us k g i n by giving thr dualists' claim-that the mind i s not a physical iarn-the bcncfi~of l c doubt. The question then rrius: Whet h the rclarionship h r r n this nnnnhr\iral irrm an4 thr nhvsinl hod" t h ~nrrnmlnnirs l i t around theworld? ~
.
~
~
.
~
~
. .
The problem m m commonly u&agninrrCnrtnirn 'k mnmb d on xrnr o(.y,ongund;n% ' h r n ,&ns ~rni.b.rnd in m m n r , rMhn am. him6 mi*? h.rr Dan ""dl"% b $ ." d inn,am. .lhsmxr. M"aa~m..,.h.r*in~,hi..rrdmcum u n r k n n n d ~ b a m . nRilrhouwxmthin. ~, h."c placer I -r
Slmppd t k
iknO OflWroprhlr alninn.
Ih.rb*
and dn let m k n d
-
d d h m ir Haw do two
such d'ninct iton-the body and the mind-nunage lobcpanr a f a d n d c o v v l nctvork? We undenlud. m think, how the physical cm afhcf the physical; bur h m can thc nonphytal do w?
APPENDIX I
764
I
SOME BACKDROP
The argument has mmcfarcc. ~ n a i . n d d i s m w o u l dccnainhgain inphu. ribidiv i f wc had romc such amunt. Still, m illow that many thine thal arc not at all likephyriul obi& may still sa on them, w i m n r (to taker darsic -1 the imn filinp acted on by. magnetic field. So ilir not ~bviovsiythe caw that cartesirn inembioni$m is mneprvally implaaiblc. h why give up dudirm? Dualist doarina of the kind outlincd a h haw k n largrly absndond by science md philoraphy. The mind i s now taken to be gmvndrd in ihc ~ h y s k l body in such r m y thar the problem of intrraaion need not a r k . M m y factan haw mntribvled to durlismi downhll. Pmbably the mart important dlhac are the fallowing. I.The obvious drpndenrr of the m a u l on t k phyriul. D w (wwh u Pmw, or -"s,), which sffeathe phyriul constitution of the b n i n in modnate17 wdl vndcrttmd ways t ~ t e m a t i d alfcct y our m o d s m d cmotionr, Bnin &mace-foreumnlc. an imn roikcthmuph the mehonnl cortex-hlilrcwise disrup~ivc. The evolution of intclligcnt n n t u m is conelated with changer in brein nructm. M rhisruggau (as prewntd in Churchlmd. 1984) that m must a1 Ic-t I m k for r yrtcmark conclarion of brain activiq m d mmtal activity Why. then. asurn, that there arc mr, i r m h m in need of mnrlrion. inrtnd of ow ilm a varictyof pmpmie~? Msrrirlls-hc rheris t h r l n =re denling with jua one k i d of iten or rubnmce, "r p h y r i d matar-ms to win out on grounds of simplicity. ~~
0~
.
~
" .
2. T h c p a ~ n w u y r n m l ~n s famr of durllrm rrcunronnnring.Thnrrrr 1. #he- h m could . 3-argummt. and (hl ihr .gurn.nt horn ulsolpnlon. a. Ihc-how rould 2" anvmmt rdmon findin~oroannoihurnamk. ings and asking "Now how could any mrrc phynral syrtrm do that?" h r u r t n suggeld that rnvoning and ralorl~tion were hcpnd any mcre phyriulsys~m.Butta&y,xiIh our inhlitionsmoldid by rhopr fuUofP8lm Pilos, G l r and -n modnt p a k a etaslula~orr,wc arc unlikdy to c h m u crlculsdon to 611in the blank. Now poplc arc mom lilrcly to rhoov mmr abilit).likc"hllingin Im;"lppreciatingarymphony."ai "bcingcmtivc." But work in ntvrowimcc and anificial intclligcnccis rtndhrllycroding nllr thrl t h e n a r e vlrncihlnm that no mere ohniral mtcm could m r .. faith .... ~~~-~~~~ do. As such, the fa<$h a t w do X, Y, or Z no Ions- <cuts much ire rr m sm ohvriul . Nnrms. . " m m f to ihc effect that nrannot mssiblrbe "mere". b. The argument from intrapmion ir r harder nut to crick. The i d n is that we just k n m that r bclicf i s not r stare of b n i n or body. Wc u n tell jusl by1ooking"insidr oursclra~and vting what r W i n g h like The tmuble ha, ia that inrmpmion is a w& IYnd of widenu. Granted, we know that our feliclings do not rnike ul rr k i n g brain m t n . But ra what? Imay have r feelinling in my srommrh that docs not strike me rr bring a mild caw
.
~~~~
~
~
". .
..
~~~~
.
.
..
.
of ulmondln. But it might *ill k r mild c a r of ulmoneita far 111 that. This avnrimplifis the b u s bur the point is dar. Unlclr mmc-
one un rhowthu what introraction rrvnlscrnnor k ihc lrrvrame [him as a bodily state, albeit under a diffcrrnt drwripdon.
d"not rccqt
intmrpmion rr dccisirc Nidmce in hmr of drulirm. Dullism, then, lacks cxplnatory fand independat poritiw N i d . ~ in its hmr. How clw might we conceiw the mind?
2. Behaviorism Pmhbly the f i m major philmphicrl madtion aminn Dunlkm u m r rmr u r rcr d t o f lhcnphatoryinrdquscia justdewrikd, but i n r t d p o u t o f r move mcnt within philomphy that is ramctimn rcfcrrcd to i r the lingvirtir N m The Inding idea &s ~hiloraphiol p u u l a w r c at mot puulsabout innpap. Gilbm Rylc. in The Conicpi ofMimd, published in 1949, a=d u d i i a d ihc whole body-mind d.bs,c of. failure to vnd.r.,snd thc mlc of mental talk in our Impage. Philoropby ofmind.a~cordingtoRylc, wucrptinted by I)rrmner'mp'k And Daunes' my?h wr, in ctkr. the i d n of mind i s m inner sanctum known only' bvintroromion. Thc mwh inclinedohilonnhcrr torrrk some account ofUlo , mlarion of this inner sanctum to the public world of pmplc, abjms and actions. But ihc t u k w u thought to be miwancrivrd. Philoraphers, Rylc d a d , were failing l o vt the significance d mental talk, in much the umc m y rr rammne fail9 l o w the rigni6cancc of Wk about a vniwmiry who, on being rho- the library m d < o U w m d playing ficldr m d tccommodrtion, goes an to camplin. "Ye. I rrr all !ha!. But whcrc is the uniwnit,?. The answer h that @heuniveniq is not m w ~ h i ~ ~ r n r r , 111the colleg% accommodation, and lo on. I t is j u t the orgrnirafion of tho^ very item& ]us so. Rylyl.argued. the mind is not ramcthing beyond dl iu public bchavionl mrnifertrGantmindlnLk is just a m y of talking about the orgmiution ofthc behavior itself. When we a y that May love teachiog, ndo not mean thar insidc Mary thcr. is gho+ lming that iluompanicr her pmfcrrionsl sclr h t h c r we m n n only lhrl Mary's m u a l and potcmial behavior will foUows certain pnern. That paltern might be e x p r e d u r wry long conjunction of claims a b u t what May would do in mnrin situation& r.&.
.
.
.
*
i f she U offered a new t n t b m k she will tsLe it: i f .amcone a s h her i f she libmching, she will my rn i f she wer a gcd tncher in h m , she Will m to emdale them nndmm.
The idn, in short. is that mmtrl trk pi& out k h a i m l divriMnr It b. I a t a w h n m m d ao ir likdyto do in such and such circvmrtiI t d m no1 pick out a lutr ofam inno menu1 sannum. T h e clauic analogy is with 'hmirrl Xi.
rspENolX I
166
/
SOME BACKDROP
positions such as dubilily. To say that x i s wlublc ir not to rry that X mmrinr wme hidden spirit ofwlubiiily. I t ir jwt tomy that ifyo" put Xi" ""tn.X w u l d diwlvc. Mmtal l d k picks on m o n complex dirpoaitionr lwhrt Paul Churchland (1989 calls "multi-tnckrd d i s p i t i o n i l ; but dispositions is $till a l l f h v an. I h r e wnia afflictkhsvioriam in the form Ihare p - a d it.
I. mdirpai!ion.l
malpnr lmluetthm tnfinrsor ormbr. I t will hrinfinilr if r hawe to is, what a g w n blod will dnpopow an agnl lo do in w p a o t b l r I,?uooon thnrould be I". ~ n 81 dn l l k r~rcui., it our I,,, u f d u ~ o a l m m mLn imduciblr rcfornce la 0th" mental states. eg.. Mary will iry lo lm'h well a long as she is happy and docr nor klim rmhing b ruining her life. 2. The dispparitional account vcm m wnt m rule out the inner rlnctum completely. Bur isn't fherr wmr truth in thc idca? Don't we have inn" feclinp. rains. imree. m d the like? 3 It a nplunamnlr ~ n l l n uI!rclls u.at k t . mmnhmg about how xr uu m n tal concepts Rut fhn need no1 be !he m d of the story of mnnd E\m ~ f " ~ o l u hlr' un nm~'w~ll( d,unl\r in wtrr.' n 'an A& anrr the nou&of ihr disposition to diialvc. We a n A how it is p m i b l t for wmrthing to dissolve in wtcr. So too r may ark hew i!i s porsible for rommnr to love Inching. And the n~lamalionshould appnl to a range of hca beyond the surfsic khavior of the t n h c r . ~nded,t r h n at hcc vduc, khavionsm ucms to commit a kind of "mnhod actor. f a l l & (we Purrurn, 19801, ann%ulinggmuinc nwnlaatrs (of, ray,prin) loanyoncnhibitingappmpriaft khrvior,anddmy. iog p i n to anyone able to supprru all l c behlvionl and verbal .xprn~iO"l of ~
~
3. I d e n t i t y ~ m t y I n the mid to late 19% philmopkn kgm to mli-r divrc-that l h m was mom to philosophicd lif, than the ."+is of the conccptr o f o r d i n y l l m gurgc ~hilowphycould, far mampb confribae to the nvdy of mind m d mcnt r l m ~ h r n i r mbyerunininglh~concepl~ulcoh~mrroflo~ntifi~thcorywhrmar. r BY this Iman. no! ormining a particular. WU worked out wirnrifir thmry in uy, nrurophy~iology,but by conrideringtheinfcliigibilityrnd impliafions ofgcnen1 ma 01 srIcn!ific .ccount of thr mind. One w r h a
R-ns
to doubt that it doer inclvdr
I.kihnk' I r pmblcmr
2. +~ch*uvinbm
objection$.
IN.
kibni2'law srercrthst if wodncriplionspickoutthe umeabrct, thenwhat. mr is of theab* unds one description must bc me of it undo. the other. Thur, i f S p i d r n n rrdb ir P m Parkcr, then what-. is m e ofspidrrman must be true of Pmrr Parker. m d vice versa. I f Aunt May is Peter Packer's ailin. &. ti-, tben she mwt be Spidcnm'r riling rclatiw =Ira. i f S p i h v l c h g r tomil. i n s then P r t n Parka must ding to ccilingr alw. Fomrily, l X ) ( Y l I(X= YI-(F)(R(-FYlI Whatmr their opinion obaur Spiderman, m y p h i l m p h m wtre unable to m how the mind-brain i h l i t y their could live up to the Lribni.' Irw mquimmmt. Far comidcr
. I S p t i d I m t i o n l A b n i n nrte may be located in space. rsy 10 cm behind my
.
ryrball. But i t sunly won't be lrur of any mental sut-y, mybeliefthat Mark M c G u k p l r p for the Clrdinrls-~hn it h 10 on behind my cycball. [Truth nluel A kliefmaybe true or f& hlw?
Bur how u n a brain slate be true or
. .
ISemtiond content1 A p i n may be sharp or tin&
But could r b n i n rlrv be
harp or ti& IAuthorityI Irmn m have some aeharity aver my m m t d rlrtn I f Isincemly klim Iam in agony, it lmlv as i f Imust be right. But Ido not wcm m have m y l"th0rily over my brain $,.,a; n ncvrophpiologbt could rvrcly correct me vith r q m l to t h m .
one w y of mspond~ni to t h e objrrtanr IS rtmply to j w p the nmlc we irr offcrcd m d say. '11 may nnl m 8%d hnan >tamu n he twr or frlu. or mmlal nato l w n d in rnxc. but !he arc' I t d m not urm as ~fa dash of l #"h t n t " n tr a n clmricd dixharcr. " but i t is. And if wu hare wme nuthnin whm it Comrs to spotting lluhaoflightning,thenpu haveit when itrometarpaningmmr kinds whether you b o w i t or nag. The i d n behind this kind of of ckrri
. . .
~
~
~
I. Mary Ianc Warwn k l i c v n that Spidman h a hem. 2. Mary lnne Watson doln nor k l i e w that Pner Parker k ir hero.
w. 3. By Lcibnii 1-PitaParhr is not idrnfical with Spidmm.
168
*PPLNDIX I
I SOME BACKDROP
ldentirylhroy thus auniva the Loinir'Irw .+is. Hinoriolk, it luccumbrd (although sophishiJricared&als an incrnringlyppuIsr today) t o a vny different kind of objection [fint r a i d by Hilrry Putnam (1WO) in a vrin o f p l p r n heioneof ~ ~ srpaiu-rhaudnir ginning wilh "Minds and ma
~
..
some B&mp
369
wmman=liv in vim. of which s sundial. a clockwork dam. and s q u m z digit.1 dam arc all u i d to bc C I Owhat ~ unira thee dirparsrc physiul objccu b rhc purpmr, h r t i a n , or u x lhat we &rig to them. lust so, it ucmr,t h e nerd bc no uvful physical d-ptian that u p t u r n x*ut my anger, the dq's anger, rhc Mmian'sanyr,andthe r o b o l l r n g r d haw in common. Inmmrwnr. it l m k d to bcthcfunaionaliwof thedifferen, ahvsial date that r e h o u r several rnnn - ~ that unite the s a t e o i mgen. Hence. finmtionalirm is r %hem= for s xicntific t h m y sf mind. one ~.yofundmmandingtkh c t i o ~ d i arppmrch r is by rrnlogywith
..
~~~
~ -
~ . ~ ~
CI 'Ihc mind is to lhe h n i n u the p m g r m is lo the muchine. but
C2 Thcmind ira program, run i i i humms)with thr b n i n ss i s supprting hadwar<.
C2 is often nlld olarhifindiowlism. Since much of the prrwnr im is w c cemed with version8 of machine hclianrlirm, Ishall not pvnur ,his po~ition any huther hew.
The &I u,hr h u bccn to ur what g m m l kind of r h r m a for a r t m t ~ theory h
The 61.11 m r c idrntiv thmrLt hrrd a hopln, 8uL t o n , rc Drnl.1 MMI has poanlcd out. to findong 2 purely ~h9k.l arraunt of xhal all rlock~,uy. haw in rum!ooon. U'e would find no u u h l dmnploon. on #he:mgr.geolphpic*of lhc
~~
w of ihc mind?
Sam= would v r d this a, r mirnkrn goal. For i t reems to ..rum. that cur commanvnv ideas about mental phcnomma. which ,-*her make up our
,
APPENDIX I
'10
I
SOME BACKDROP
really are such things as h o w d n i m , fnr* bclich, and so on,m d that the job of uicncc ir to -bin them. But, d m 111. people once thought that t h m mc h o m s n d n m p i m m d t h ~ t ~ p p s m t l y ~ ~ ~hympI~riwscthcr ~ ~ ~ ~ f i l k d a d much clsc < h awirnss has ahom to k miryidd. Imagine, thm, r discipline devoted to investigatingwhat kind of wirntifir theory muid parribly rcmunf for thc cxistmc of the n h e . What li w a r of time! What xxmu show. is that there h no cthn and ao the twk of accounting for itr Nstencc never .rim. Could the c o m m n r n w notion 01 mind m e a rimlar fate?T h o r who think w, all themnclm rliminatiw maariollrrr (r.g.. Chushland, 1981). The task of philosophy, aa they acc it, is not lo prejudgethc irrue by simply wning out to d i u m r what wirndlic uhema crplrins the commo-sr v i m of mind, but dm t o critically examine wicnrific accounts l o x c r h c t h n thc commonr.n$c view ir w n d . One a@", this is a topic treated in the main tm and Ir h d not punue i t hr here. Nalice, however, that diminrtiv. msrcrialirm n d not be m 111or nothing doctrine. Dcnnm (1987). for example, allows Ulat come of our common .=nu ideas a b u t the mental may 6nd r homc in mme future rcicntific theory. He jurt d m x l ,hat we should demand that m v .ood ihcow caDhlrr dl our nrerhmretial inruirisne. The most radical versions of climinrtivc matcrialirm prdict that nrmally nothingofthc mmmon-re h m o r o r k will bc p-&. Ed&&, ddnim, h o p , and rean will 111 be abmdoncd in romc rumre k m c c of the mind. 1, i~ Isu~pn. extmnely hard to wm mnkc rrnv of this d t i m in odvnnn of ihr v i m k i n g donlnpd and offering ur l l t m r t i v c roncrp,, to u x when vc formulnt, it. From hcrc, i t is hard to wc haw such a hfum wiencc could her wimcc of the mind a all. But that, of
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h r d -nt tmbaob off" suoerh inlradurtions ro Ihr noaim in this.olmd~. I-wuUy rarnmmd I.Kim. hilomphy ~JMind(8o~l&~:a): Walvio*, 15%) md D.
Snddan~Mi~hdl md F Lrhn'r Aclwphy ofMind md C W m 1Orfo.d. Errglmd: slaaweu,LW. 0th" uu(ui tmmensin
A P P E N D I X 11
Consciousness and the Meta-Hard Problem
Rndcn of some n r l y v m b n l of this t u f l u w f e d that i t prid im livk nnmtion to the hot topiu of mnriovsnnr m d rubjmive np.mcr. Thi. wu no rcrident. But i t i= undmiably the uu that r complcfr m d satisvfyingvicntific ae. count of the nature of mindware cannot remain lorsilent conrrming what ib srprhly. the single mon puuling f i a ahbout mind! I t is with romc mpidatsn. then, that Ioffer a sketch o l the irruu (as they i p p to me) and a fcv cririoll m d constructive remark Conrcioumm has mtainly come out of t k dmr ARn n bng pniddutingwhkh t h c w o d w u hudlymmtioncd inwicntificdrcln.~onkournnrirrmw thclur of8 majorgrowth indurq. Thrreirr bmk meetings, mdjoumab* am lnrrma diwurrion gmups and web dteb Thereb hope, interm, and o ; r i t ~ molt. But is thcrca thmiy-r even Ipmmiingsknch for r aoiy?It b.suangely. rather h a d to sy. ~tia hard ro because fia,the word "conwiourncu" d m not e m to rim at aringlc, nesdy m r p . We need to distinguish uariour pssihle tnam and athe s t a t e o f t k r n relstivc t o w h one. And ~ e o n di,t b wlnr (especially with r a p m to wrmc ofthc more m o n d i r h r g ~mrtlywhat ~l would count ar a thmw, &etch. *or*, or unlanetion, mmrv. , some p a ~ i b l ~ t r r g cfor t r s d m l y of mmiournou include r i m p k r d rdf-rwrrcnss rvrilabiliiy for verbal rqort, rvsilability for the wntrol of i s m . tiond md, ~ r ~ o ~the r u , of #he f&or qulis. the d i d n o fels m d rmstians tbat mrkr life wonh living or (wrmetimn) worth ! w i n g Simple rwrkmcv m y be mughly dBncd u the rtntc in which we are quite rmririvc to our surroundings,able lo p r c e s incoming information and rerpond .ppr~pn.t.I~ Srll.aruennl onvolrnil,r < a p u l N ! o r q m m l ~ u r u l v n ~ n d lk o wart ofouwhcr .~d#st~,,ct agcl,tr ~rnlrbdnrrfur 8rn5rl mpon tnrclrn both o n.a o w. lu wmchuw a u r u o u r om rnnrr 'ta!n m d t o d r r r o k ~ hw ~rindt us ing words (or sign Ianwagc. =I~vailabiliry =.). for ihc rontml orinrcncional idon
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ruegetlaacmrin kind of'infarmrtiotul poi=," such that some of our knowledge or idas become u p b l e of guiding nn opm-cndcd n n p a f pmjrdr and aninti-the kind of informational poke that Y mising in. ~ g . .a blindriel pticnt'r Limited apaciryta ur rirdinformation coming from a 'blind" =*on (moreon this klow). ~ n q~alia, d n w feels? 11h dcprearingy hard to say much mow about oadywhat thnc are. WI-it lo lhr wcll-worn hints and p h n u r ihc very ndnor of the apple. ihc tanr of !he p ' h . the prr.,w and vnuftrrzblc p8orangnru of lhr pnd,and u, on 3s I-n Kmm rncnllr put 81. 'If nhor docan't help, prrhmr nolhlnc " nll' lK8m. 19% o. 1800 . Thrrc is samrlhing striking about men lhir p n i a l lin of pmribk lugeu for aIhmtyofconuiousnns.What irrrtikingirthstitiso~thcfindh r g e ((.qual~"l 1h.r ihrcatcnr to prcwnt any rpmal kind of pmhlrm for our standard mod- of cognitive xicntilic uplnn*lion m d undentmding. All the r a have to do tither wilh whrr i t ir wr are informed about (what, to bcg ti f w qumionr, is inrrmally rep-fed) or wilh the m y that infomutian is p o i d for the contml or srrian 01 for $haringwith ofhrr wgnitivc ~ ~ h r y t c mThmricr s. about informafionoi contmt and infomrionrl poise thus have the mourccr to explain a largr p n i o n of what L &en meant by "conxiour rwreneu"The quntion is, u n t h q go all the
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To gel mmc r n r c of j w t how hr they mn p.mnsider r h m bodies of re~eenrhin cognilire neurawimcc: work on blindsight, work on bindine and MDn n and Goadaic'a (1995) mcnt work on dona1 versus ventral pnxrrring. 'Blin&ightP noma an intriguing phenomenon that has brcomr one of tho r u p l n of cognitive scientific conisrum concerning Mnwioumcrr. Blindright patirnl, haw damagr to ,he nru.1 r o " a , multing in the pracner of a sLo,amr or blind spt. Such p ~ i c n cl+ s to ur in thh region, hut o n , i f f o r d to guru, pcrform way above c h m a (Weirkrmtz. 1986). For namplr the patimrr can ~ u r ~ r u f ,u "l l r s uwhahcr ~rr s l i"h t has flashd in the blind .-in" n. .and can m n oricnt hand and wrYt in m p n r to rhc r h a p of p r a r n t d o h i s u (Marcel. 1988. p 1361. But when irked i f hey o ~ u e lhave l ~ visual experienceon w h t h to b;lw t h e ru-fol mrpnree, they either inria thcrc is no nrpricmr 81 all, or qmrl somrthing faint, inrandusiuc, m d not really visual in narurc. Thr arurdatd arcount of the condition h u been that the auaeuful rrrponrcr arc r m t d in primitive. mid.bnin procesing and that full.flrdpd phenomenal conwiousnrsr Ithe crpcticntial quality, n w frrl, s r ) thus dcprnds on thc more ~ ~ l ~ t r ci m~t ~ r i l ~ ovrrlay oihsphn coniul minty. A compmng account, horn,, rrplalnr blond. 18&l u the p r ~ w a f t o nmthon the w.caIId blond q u n of small rrr- of prrwr,cd nvun-nwrl 'hut ,a,,,ha, on., r ron,ul rovtr to ihr ru.r.sshrl ms p n u l I* Gaurniga, 1998, pp. 6 0 4 3 ) . Either my. what nmninr inr.guing h the ptimt'r denial ofactual visual nrprirnrr in thnc osn The kind of visually guided anion that nc ordinarily t r k to k indiarivr of visual rrpcrimcc is h m prnduud uithout the a
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171
simplidc-thought k find the key ncvnl differencesh e n the nro ~ a vand r p u haw found the phyiologul rrrt ofthaw ever-clusivc qudis. Anolhnfunowncumicntificmnrtibution lothcdcbatr L C r i ~ k u Kah's d 11997) w o k on comiournnr and 40-Hzmillationr. The focus of thework h o n the n m n l mechmismr that achieve binding, where binding i n w l m ntablkhing r certain rrhtion krwen nrunl populationsarryingdiffrrcnt w a n d ilcmr of information, c.8.. binding MT motion detecton la v 4 hue dnmarr as p n ofthe p n x s r of rcpmmting rcmin ficc in the act of ipnking (we Ctidr and Kah. 1997, p. 2841.Such binding, C r t k m d Kmh d i m , i s r h i n c d byfrqumq-laked mcillationr in thc various neural popuktioru. with ,he locking p r h r p mediated by rircvitty linking the conex to the highly connected Ihrl=mur--the m-callcd lh&mmonid Imp. S p k ~pchmnialionsin the 40-Hz nngc larrualh/, myp where h e n 3s m d 70 Hz) rrclhm depicted as joiningthewriots ncursliyrrp m a t e d featurn into icohmnt whole, which is then placed in working mrmoy, which in turn rcndm the cohcrent p m p t p o w for the widcrpnad ronsol of action m d rep" (Crick m d Kach. 1997. p. 181. As a fid wurrion into ncumicntific mnjrclum. mruidrr Milncc a d Gmddc's (1995) amount of thediRrcnt functional m b of iwo mrtemi
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APPENDIX I! / CONSCDUSNBSANDTHEMETA-HARD PROBLEM
8 74
rc1A4ry. and thrdaimthrt "thepmsringrcmmplirhod byrhewnnrl s t m m (inv o l w fomr of mding that] coincide with thow that render the reprrsentrdons aumiblr to our amrencrr" (Miner and G m l d e , 1998, Smion 3). Our oemplar nrumwicndfic ncurrionr are at an end. Bur the vning pmbkm remains: What u n this Ljnd of midmrc, thcoy, and conjmturr tell urabout the phhmomcno of conacioumm itwlP The msmr, namrally, depndr on the l,,rccir, r.m we t i w to ,he wrlvlword "rnnrdaumar." rnd on bow wc conccivc ~~the whlion h e e n the various phenomena ef a m % poi*, roonobiliry, and q"aiitati"e ki. Onc influential mwr. at about this point, b to h l y d i r l i n g u i r h h o notiom One L what Ned Block 11597, p. 382) ulln acrmsonuioumnr Theotho L what Block (1597, p 380) -Us phmommal-mnuiau-. A m - c o n r i o w n c u is d about informational paiu: "A s~rrcis A-canrriour i f i t b poked for d i r m control of thought and aaian" ( B l a k 1597, p. 382). When information (cg.. about r virurUyprcslnt object) is able to yidcisenrionrl rdon and verbal repon, itrounu u A-conscious Phmomcnsl-con~ciousnm,on t k ofhcr hand, is something xc annot dclinc but ran only "point to- (BlocL. 1597, p. 380). It ir about the hlf quality of taster, rmellr and
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Condoumen and me Mem.Wsd Pmblem
m e . Wecould mundostadwhy, for m p b rcrtUnkind8drilic~n-mr&Iable it8 npnbditia ofobject mopition and p e n , while leaving inlad iu aprciry n, rcrch m d g a q . Bur we would not br one whil do- to understanding ~ bi ttis abovt u thrt uuws the phrnommal -'mrrrh~, in us. acrompmin vrnml m c r m pmcuon8 lor 40-H? ncillation, or whrlcvcr) The alca that currmt nent16: ~ ~ ~ l a t illumtnalc ~ o n $ *mu-
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APPENDIX 11
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CONSCIOUSNESSAND THE META.HARD PROBLEM
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conscious of s~mcthingc l r c t h c world we liw in .nd .the mndition of avl o m bodan'll rr an o p n qunaoon ~mongmprrvn~~lnnJlstr 10% how to unpack the m l m n l nnlr,n of inlrmal rrpnunal8on H chaelTyc. forr..rnpic. hold, @hat wc need no! orcnntrllccnul~u the ldcs 81 ir ncsl chat the seen! s~ has to dnrloo mn qtsruch a "tisue damagc." Rather, the pain may conrirt of a ' m r m y n p r m tation" whax content fucJ t k phcnomcad c b m t c r (Tyc. 1597, p. 3331. IA parribly dated pmpnul, with m rrpnmcntaWncumrcientili~ spin, ir raluidnrd in Oor AII.I.1 Rcpmoltaliondirm r l m w m n in hw dirtinn p d n : simple, or firssocdcr, q r a c a r t i o n d i r m luabove) andwhat has brmrnr h a m as hi@nordrrfhou@t throy. This latter is the idea thar a neural naa is phenomenally conxion%whm it ir inrythe obi& of a thought Roughly, to f e l r nabbing pain i s not ljunl to rcpreunt r ccnein liind dtirsuc damage. I t is. m l k r , to have r thought nboutthc rep-mtion of tiuuedamege. As Rolmthai (1997, p. 7411 lur it. "a n r d smtr will k canwiovs i f it ia rcwmpmied by 8 thought ahout the narc." Why h r rcpracntationrllR? The rnradion b bath pramid ~ n thmretietid. d On the theory side. it can k argued t l u l dl phcnomrmlly wnwiovl star- mvsl invabe some kind of rcprcwntationd canant. Even the much.cited o v m a n . i f a m b sufficiently h s r d - a d , k claimed to be about ccnain bodily w m a m d p m c It ~is 1- clear, however, why wc should hold that such conrms ahmilt ih. phcnomcndfeel, such that acmunting for thcconrmt simply k*cwunring for the fuU npetirncc. Higher order vmians. esperially, haw ramahing to s y here-bur Ipoatponc funher dircvsion of this until irtec. The pram'rai anrztion is, of m u m . undmiablr. We hare a much brnm " pnro of lhc notion of contmt-cam~~~~~~~, ins inner states lrrprmtnrions) than we have of q ~ d i raw , klr. and thcir ilk. (For m y ~ l f I . uc nothing wmngwilh lookingw h m thc light is brightat) fimsll7 la kind of mahodologrcalpoint). i f r di%rcnce in rcprrrcnnriand ranlmt un. indnd, a h n p be found alongidc WT I differencein phenomenal feel, whs p o r Able wounds could w haw for inriains that t h e ir $om-hing more to nphin? A second gap-denling repmonte, rdatd to (bu?no, idcnxial with) the first, ir what Iam calling 'nrmtionirm." This is a clumsy term. but it capturer the porition bmcr tbnn in rivals Ioqualii nihilism" (Kim. 19%). "climinntivirm." nr.1. The otignaot and ptime mover of nemtionirm b Daniel Dennett, md it ir bir lcomplex but m r d i n g l version that Irhdl, with romr ncpidation, now rm to rke
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whxn urlol. , a m olUmmd tool."(Dmnnt. I w h C h l p l n S l mad? avanlablr bv our rmmo%lonin ~ l N r md e ilngugc ICmnot h o p l O d 0 lUVlC< l o the hr I nary h m But r not tw m~rleadcn~ Anch mlyh< p lhlr this
In ~ I m Y k m* m , *c s t q pe mrIhhg We this. Dncdon of N-nhrlwc--brudbthc~~oninmt@mdbidagi. d *ems d " r m r d and pnirhmntrm--m up sn mq of vhst D m ti0 & 'roml* ah' A somatic muk- Is a Nt.th.1 tin thc in.gltnce of .o w m t t o i y t &buerrion, ifw f a i l 4 amxt(on, if* ~ w a d c d r d ) . Thi.mukn ryrmn o p n t a a u m m a w y C i m r m d lubM) in fumm airml.rmcarnterr inavcndng bathal-thrrparespnmsnd the amq ofopioru L h . 1 ~ 1gmmae for Frm*dmd Idlrnir. mion. Ihr mH m d loundatiaoofthk ubolcryacm a n our uptin/m wnu our ow0 bod ilv ~ ~andlavsliitillh) . ,. innate ~mlivitvto n)r some such N I L . u 4 (~1easunble)mdcthnrarb.d(p;nhrll.Of~pddimporraouhmr*our apacifita to dmn and repmen1 imec biochemical ate, n.aa of% vir. rm.md &in, and of the mvvvlwkarm qusa Hrrmn mucimw a m ir thw uid to h rowmlly i n f o d by n ~qndifylngt d y ate.: .a 8,&msio"-~ a b y e wnrciavrly fdt-f r p i t i v e or ncgtivc W stnte. E m lrhar w uc thinling of .onbodily mrnen (mrlling r Mthc m a t i d Rhmm, s y l vr ue said to k I m n t i n g n b o d ~ a iomUndon p tha has k w r n r d t d with the iinm, p n o n a, m n L 1c ,i the caotinvov, -ce of thu -cited body n u "im*," vith in p i t i w or qaliw @, Lh.t wr m s . iU d o n d tone dm mr*a the h.~.tb.m,,$-t.rthe~~ngr~,rhnmllatbrMing OMS acmrding to Duouio, Y ram pby which the W tSelmth. kcoms r o ~ t c d r dprbrp ~ r pitnpur in thr urmtruc. 6on d- wnt qt-tarion of tbr self l u b i &tmd
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APPENDIX I1 I CONSCtOUSNESS AND THE META.HARD PROBLEM
178
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&Mirr5ndmi,mdou~~~th~-,h~.1tirclnr.
~dutWhilms~~htnhtromevuidacflull-blm ~ o g i c n l r ~ t ~ ~ ~ F e l i n g mib&ddI.meeflheprm t i a o dim of phenammal@d mladdarand Damasids claim i s
Ichin bcdy.rUB rep-ntaioml in jumporition m the mrlltal imsge Ihn initin& th. +c' (1994. p. 1151. Such a msnrskech can mrLc it e m u if the rcmunt--coosidmd u n stmy .bout phmomd@giul conscioum-i~ quahn k n g . Surely wr-temlrin oh-d mnwiavncrsbva~mllo ~ h n o m m d s h t n of pin. c, p1-, or ' p a .ad neg.tive- qina But he, the atoy u mum dsetrr. Tb lh.clnim, u 1 read it, is no! t h r phcoomololckcal mn.dau~lt on gmr or rubtk (xc~ground^)emotionnlsiactink Rnhr. it ir mu phmammol@d r M i & in thew cj u t i the junapmnioo ~ f b o d yinmy ( i c l ~ ~ d i n g m input, i srquitrd positive and n q itin &tam mod rn 01. vnh p m p d or imginrtivc pmcerrinb
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I
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Fin1 mow: Th. 1ntedonrl Slmc.. Thc idea h r r m r m i n c d in detail in Chapcr 3 of ikm!-$$ that a mlm has a bel8efps m c . w ar behanor or nll prcdmd by lrcrl~ng1rr a bellever Tho, u 21 venom lIW8, p 3311 note. 'm~x~mxur nrmluow undcr.tandme-.' whrh makc, n o rrrr06< rl=omsrho"! an~~, ner mudurc or oganiration. k o n d mow: Multiple Dnlh. 8.ud on a "ari* of neu-ientik m d mgnirivcp~holo@cal6ndinesDemm lxtdu, Demnt and Kinrbovrnh 1992) dcpicts the biologirsl bnin r, the lacur of multiple. quadindcpcndmr pmaring rtmms. n c r c is no single, ultimar judgment i u u d by ihc brain in r e p n u to sn input-no dedrivc moment in apace or timr when the r(slmv l t l n on a uniqvedmni!irr
~
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suprisinsly largc mcarun an artifact of our immcnion in human cultun." Our nmrordinay immcnion in a rra of cultum and lmguge liuclf, to be rum, made poa~iblcby romeamalldifference in innate hardwarc) m a t s in r k humrn bnin, a nor kind of romitlw o m " n i u t i o r w nrv"nrtus1 rnarhinc"-that sllowr us to m&e cogniriw ohjmr of our o m lhavghr p r c e r m crd to m v c r kind of ongoing nrrnrive (about who wc arc, m d what we are doing, m d why we a n doing of mum, not nit) that anificidy "fua" t k cognitive coaens. The w n m t i*, ally furd,&ruse undmneath the pcmnal-lnrl narntirc rtmm the morc hmdamennl m~ltiplcpracesingrtrrom nnrtill going like I e drppcm. But there i~ rouncsy of thc new toplevel virtual organization. a smiking difference m now .*on ihr p m c n ~ c a i a(plll.stneam 01 crpn.ncrr a rtrnm, r i you nll.of)ud*. or m m r d m n p . I" whtrh thnc v r m l to k I
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APPENDIX I1 I CONSCIOUSNESSAND THE META.HAR0 PROBLEM
180
-4 whether i t is anilablc for n r b d rcporl n r . ~ n we d cm rec,in b r e d ourline. how r+c ncvmrirntifir or campuutional mnjrctuws might explain ruch nsttms bindint,~ A lo Crick and Kach, will rndl in failurn , -d
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bod (Kim, 1996, p. I80 citing Blrrk, 19801. Such a rnpw rhauld, h o m o , dve us paus. I n no athc. xientific or phinmphicll drhalc would such a move k acreptrblr. Why here? There i% ~O-I: a d n r Y ~ iY n which a story such r. Dolnnr's d a nor ignon the fimt.pnon pcnpmin. For i t iz we uu,of the mss.nce of hnnm's larger story that "our lhumanl kind of conwiouanarmir crated by rhc dfsu of culture a d linguistic errprime, which conqirs to innill habits of thought that ruoyort . . 1-wc~-illuion*-th iUvion of. unified mnxiovanru xhm dmkiona and judyrcnls farm thcnrrr=tive chain that make us who wc are. The distinctive feel of our firs-prron perspectin is thus n p h i n d . But, in a &in wnw, s i s pmnhoodthst now rmerges as the primary. alturr-driven dicvcmmt; i t U fhc xnsr of p m h d that givcr human mpnience im rpccid rhmaer. Y e there w r m s to be a tmsion in Dennett's position hm. For, on the one hand, Dmnm mnu to daim that thc hn. of mystoiow qudia arc -infltingdifferrocn I"drgrrr lor rich-. contml, dr.1 into [email protected] diacrcncrr in End" (Dcnnen. 1537, p. 1191. But h r alio m u to claim that humans rally err difnmt. courtesy ofthr alture-dcpndcnt ucr-illurion. In odn lo h<muious-in o h r , o h the mn allhing it ir Ilk amnhing l o b c nee-v to b w a e m i n rat of inbmtiond olyniotion lonrl thn b 'ri* ~hirrd in o x .prim oum and inn, othm.. .:My 'him ir ,hi, am swciahrXour kind of wlfmnuiaumcm.. .Iam rlimingthzt w h l mu* hA d d to mm .cpon.irity, mere diuri.in.,ian, to count u
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1find i t hard to recondlcthir l ~ l i a dm n orgnirstion~ldiridinglinc among s m i n wilh mnnrn's quzlly firm inrircncc that within the human 8prie the w i a v r phenomena of rerponv m d diwriminarion are differmt only in d w e . Far pmrty clrady, some of t h e phenomena, such as the motor x r p n w r m d i rtrd largely by dorsal stram i a i v i ~ am , m o l d in phylognetidly old p t h m y r thrfwcshrrrwilh many otheranimskArlnncr.md rlill Dcnncnirn.~torymight. for example, haw intentionalr!rca (beliefs. .I<.) as ubiquitaw m d differing only in richncu of content and pix for control bmrrrn us and 0th" animals, while accepting that "our kind of conwioumeu"(which now ucm ra k the only kind of ml
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APPENDIX I1
I
CONSCIOUSNESI AND THE META.WARD PROBLEM
Thr Zombii, in A m ,ir m p a m idmtial, and inn- pmnsing idrntid, to
p u and me, but b l t n g n d l ~ !ccomidfl imwibly?) kwh of rral phmommI o g ~ rconxioumas. l The Zombie m.yl the bruises hun m d the chacolrc rartn god, but them is no expetience pmcnr. There arc luf i r s s w . know) no Zombin. Indeed, wc would nrwr haw o u r to mn surpm sommnc of b c i g a Zombie. since rhor mpanrn m d inner arucr u n arc, by definition, the u m r ar thmcof inon-hmhic. So whourn?Why fell the s!ory? Thc story msnnr to t h e llikc Chdmen) who uck to m r m y nonmntingmtconn~lion b ~ m physical n facts m d facts about phenommsl mntcnt. A contingent connmion koncthel j u t hrppnlra hold, hul that could h l v e h othcnvisc I n C h a l m m ' r i n no amount of phyrical, fundionrl, or infarmrtionpranisring.bard story-telling nplrin why wc have erptienccs or why they hsvc thc sprcific felt charadm t h q do. And onc argument, or consideralion. in suppan of this is the 1 0 g i ~pouibility ~I of Zombie. For i f you coul&in ptincipl-tiafy the physical storypt Ierk phrnommsl mnxiourneu, then thr phyikd nory csnnol dereninc. Fu, or explain the phcnommd dimension. A , Zombia logicallypmsibl~? I t doub1lc.r depends on rhr logic! T h m ih ar Chalmerr tightly inasts no obvious contradidion in the wry idra. Rut Im no1 convinced that that fact r l o n c d e s r h e p~sibllitygmuinclyconceivable. My own
Conwiclusnns and lhe
MncHud Problem
wimrins will b lpmpcrlyl puntd. I n any world that thcuirnth can richlyconrcivc, the r m r Links dlhold. The other worlds will wcm thin,"-muid 6c. tiom,' who= gcnvinc ronrcinbilin is now open to vnous doubt T h e i r e mmplicsted iuua, and Icannot go mvch fvnhrr hm. [For rddit i a d dimrrion. M h n n t (1991. pp. 518-519, 537-5411); far r ddmu, m Lmnc (15941.1 But I.mcanrinad ofthkmu
,
~~
nut let ur lnvc the te~hniolisaside. Thedy, problem with Zombis is surcly nro-fold. Firrt, they am by definition vn~cmgnirablcby any mnns rhon of "inside bowledgc." and this offcndr agrinn the (to my mind) innocent vcrifiolionism thar insists Uut ml diff~renccrshould be in principle dctmablc by communally agreed mans. Second, CV- Chrlmerr rdmin that "it is unlikly t h s Zombis are naturally pauiblr. ~nthe real mdd, i e is likely that any replica ofmc would bc canwious" (Chslmcrs. 1996, p. %I. But if. in the m u d world, thc links k m n the and the phmomenalogicd hctr can b this wrtenigh~.it is unclear why a full =ppreciarionof r h nature and origin of lhax links m u i d not amaunt tor f d l ~ n d m t r n d(for i ~ our ~ add-world purpose) of phcnamcnologinlranrcioumns iwclt Of counr, the mcri unmvmng of 1 fc* hllol.rcdncunl ronrlalrr of conxiow erpcricnre give ur that warm glow of d q explanatory undenmnd'ing. ~ uwhat t if wc unmvn r whole w r m , manblr some wry dorm the phylogcnetictw?What ifwc b g i n l o w . how mnrin m b m d dunage dlsytcmatirally -ir or
= . ~
Chalmm' mn r.rponv fa the p u d e is to t r u l phmommd e x p r i m e rs fvndmentnl. That is to say, to .rapt thar it rrnnat ultimntdy b a p l a i n d and to work innrrd on undemanding +e rhap of rhc web of cormlrtiont that links phyaiol frnr to alpoicnlial onn. lust u"nothing in physicr lcllr ur why there is mtncr in the Bnt place" IChalmm. 1997. p. 201, snarhingwll tell us why t h m ir conxiau~n~ar in the ~hysicalworld. But that d a not stop ur .eking
**
hm of noncontndiclion.
-83
984
APPENDIX I1
I
CONSCIOUSNESSINDTHE M E W A A R D PROBLEM
At the end ofthe day,the mlmystery, it m r m me, is thir: lathoc r 'hard prohlm" of conuiouncar or isn't there! 1%thoe ramdhing spcial about p k nomtnd conwiouanns that phca it outride the m c h of current rimtifir apthe other. p m c h n l n r Chdmrnmd othem brliml,or is it jut. matter ofnpkininga patFinally, whet about reprrrcntniorulirm: the thais 1.1 the phrnomrn.1 frctr tern otmpan%iuma.and report C h ~ a d" 0th- su@al)?The m
~~~~
~~
~.
~
~
~
.
APPENDIX I1 / CONICIOUSNEII ANDTHE MET&HARD pI(O8LEM
886
'IkediKemncc. Prlcesu~esa(and hen h e f o l l o ~~ ~ w 199-0 h , is w r e l y wIrcmdn, homer. unmnvind. Itrr Chdmmdlmrt (1997b,p. 3941w a n chohical. Thc"warm glow of aplmatoy undersfandid' ir the rnult of p i e h a r 13 uadlyaad. give a physicallyh v d story about phmomelul mnwiourncn b ofwlf-deception i n which w halivtinate m ovtmmr a~'almdyrontrind in lial qwC ultimatdy, as our mount of ~ h p-ing y the nmalc canuol r a m the grounds" (Price, 1997, p. 87). (Think a f tho^ old ~ ~ h r p l q i$tori-uia al N to come an, then surely the "hard pmblemmir i n d d r !&d of c c p i t i w illu. falw. dcourw-in which the nddr form wr stored i n miniature i n thc fenilizd rion. In both app* rs Chrlmcn admits the trouble comu at the w y md, when cgg.)Thcprahlem,in thr c a ~ ~ f p h e n o m r n~onariau~ncu, al is lhatourvrvdttich w unpack d thc highn lml qh"in and ask why the most hrndrm~ntrlunfor "wining"the outmmr in the r a w do not work here. But this is j u t Iw h o . dcrlying principle hold. Here, to be hridly Wiegcrurdninn, our cxplannnry rrl a Q d hurdic (not r logid. ontologid, or maaphyriul anel. owcionc end and the spade is turnd. But ro what?Wc don't ict fear of "remote Following Rowh. Prirc lists four way i n *-hich we an fool w l w l v u into rrrranlroi zombie" ( d o i c e just itkc our N nmotrr bur that fail to caulr the chan. ing cffrrts ar mnrpamnrly cantaincd i n thdr ouwr. First, by 'suing" the I n s ncis lo chancre i n rlarnrtiw.. l w"i u l l v aaniblc univcrral ih&e our faith in the. hr ofr p r o m from ground to outcome, eawhen we ~ r one c buiard ball hit nnd~tmmrgnelicfeamcwork i r fully rxpialutoryof lhcopmtion ofthcartua1,rral~ t h a m d " i m p n i" a maion. k o n d , homethin. byueingouracrions as cKKu world device. Instead. we undcntand !he device when we undersfand haw suchof our intentions. Third, by the ovtcomc as an 'scccptabie" tnnsform~tion and-aurh m organization (in r w r l d ~ u b j l c1t 0 the fundamental Lm of phyaicl) of inu u e (the kitten turns into a cat). lastly, by xring fhc autrumc rr generic yields the pnrm of cffmrw reek 10 explain. Iam not y e pcnurdcd that ext o t h c ~ a t q o ~ o f t h c n (aridruurebumingl. ux Pcrhaprwc uwother t r k k ~too; , plaining phmomenal conrciouancsr pments m y fundsmcnldy dimrent k;nd of thee four need nor he &aunive. ~ h point c is. i t ir hard to M the relation be. prohlrm. So i s thcrr mally a hard of phmommd mnsrioumes? T1Is *en canviournu. and its physicalgrounds in any of t h r x wy. It mcta-hard pmblrm m y yet prow the hrrdet m d mon imponant of them all. ~ i n a r m w , a r u i ~ e r i ~ o s ~ n ~ ' ~ ~ n l i k ~ ~ ~ ~ h ' h ' g ~ I ~ ~ i i o u ~(Price, npnpnpnpnpnnp" 1997. p. 91). Sug(lstrd R a d i a p The p+hologid tri& rrr, homer, just that tricks. Thc f.F1 that a aFor t h o 4 nnd awnmlas+w i r r w r r v i n ofnnrk all thr W m h , n D. C h h h TIx cum -lation ir rimilrr to o n c x c ~ r e a l r n d comfomble y vith,ar th. ha that n C0nw"w Mlnd (NewY a k : Oxford Univemiy Prerr. !')%I. a n hallurinateUlr cffmasalready p m n t i n the ow. gon no way at sll t o w r d For a wlmtionof-y~durwsingrhe "hanlpmblm,"ueI. Shnr(d1. Winngcbn. makingthe and relauion ontologidy, mmphpicalb, or even (genuindy) 108aiounwr. Thr HardFmbkm (Gmbridgc. MA:MIT P w . IWSI, %-yx incl~dephiio. aolly transpnrmf.lhc monl atha,, wnrn w RIIO e n i ~ u n t c o r l v~orrplr!nnrw -hi-1, ph~nommnologul.and n-urrnientirx p m p m k s . a d highlyhe include the kmds oi ihtng. wc .I,ould not rrpo any warm glm o l explanatory undrmandpirro by D. lknnsl. P 5. ChurrNmd. M. Price. C MrGinn. F Cdrk and C Krrh. B on&-not wen XI r sw wnmp the (mhu,!. rount~rfactua!.s ' . ~romlat~ons14s B n m . and F. Vsrdr. For. powerfuldrflalinn.ry tm.,mm,, m P. M. Ch".
,.
-.
~~
~
-.
.
~
~
~~~
rM
APPENDIX I1
CONSCIOUSNESSI N D THE META.WRD PROBLEM
(7-A the n m r < o m l a l e of after bnin darn^^') and by ah .nd roluma v h r l ssm-'1 am a l u m o m m e n d d m d appear in i h r Fm kiruvr r o n a m i r q Innkyg and rnwzinwnnr sx P. -8hrn m d I.M w h e r ledsl, hnws and Thoushc I n r ~ d ! m p i i n aThcmm ~ ( ~ n m d g England: . Ombrids U n i m r i h Pm- 19%). ~ m n m t s t w i b o u t ( hhr v m n m m n ~ n o f m n d ~ u l n s r i s d e t .tienah dd in his long, hard, but mlrnrining Conwioumnr+laid ( N n Y a r k Lid. B l o m . 19911. But* won&r(ully r l a r and r o m p r e d venlrrnion aimme of th. main uhrmn to k found i n &poi 5 m d 6 of his smdl poplar trc.!nwnf: 0. lknnm, nindc a / M l n k T n d en UndrrrUndq of W o u n a (Nnr York Buic Bmk 1%). Sand good &tiqua 9. p a r , along with 8 wly hy Dmnnt. i n Philaaphiml Topiq 2 I 1 m d 21, 1991. A " 6 1 ,rr.tmmn, is II. W".,"Lan *r plot? R ~ o n n r u n i n g&"".a'. munipr dm&. Ihmv 01 ronuious-'MW o n d u n p a p , II(11. IA1. 1%. finally for 8 po&l and nruronn,irwal1y blu
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H u u b l w L (1W11. %*on in t k W i l l Dmbnda, MA:MlT PIHutrhinr. E.. and Hmlhunl. B. I I W I I . Laming in ihcuhurd p n r a r I n C. Lvyon id.]. ~ m f i ril. d rr m. i, MIL ~ d d i i ~ - w n l ~ Is&ndoR, R. 115961 How lanpage help n ,hi& Pngm.nirrandCqnition. 1(1l,I-11. I x h n . F. (1911. Eobhmornmd alulu. Ph+,osohhl hzmnlr,12, 127.136. F. I I ~ Ihitnni-urnion. . ~h.raao(kr a n . ~ i d i,o r t r ~ ? ) ,377413. Ilckmn, F.. and Pmi!. P. 119881. Funaiandi$m m d broad coolmr Mmsd97(3871,
I,&.. Endmd: U m h r i d g U n i r r n i v P m * Gadwin, 8. (19951. nar the Lmpd ChmngdIuSpn bndon: P h o m i i G ~ S . .Y , v. (19591.11 mronxrueion du "id d in ~ ~ . d i ~ . t ilnter.indiuldude% ~ns rhn m 1 l k d m m o ~ n r a l o la~cmrblrnnnrrp. i~ 11 Ihmrie dr I* nip.+ h i d'inur. p m a n a n d n t-ia conrvwtmn lnrnsc&tiq 'n, 6.143. G W S ~R.. (19951. ~ m ~ l a u and o n Cqniiion. ~ h u 1);-ation. . uoirrnin olWilarnir ~ u d d m G. . 119971.I r ~ ~ n w i o u r n the o r pweption of what puw. in on.', own mind? !n N wrrk. O. flanlmn. .snd 6. ~hzeldrreI&>. me NOW* olConmbusnm Cambndgs M*: MIT Prru, 78%BW. Hafiendrle, A., and ~ l rM. 119981. . Thr Am olpieotirl illuahn on p r h r k n and peaeptbr.. I o u m a l o , ~ i t i r Nnlm-n. 10. 122-136. ~h H.. KC^ , A. s., m d nun,. H. 119851. A thmninl modcl o l p h r v t n w i h n r i n human hand mowmrnrr ~ i o l @ n l C y h m r r . 51.317-156. H&m, I.~ " dMalrolmn, C. 11W41. Rchmor. p"reptinn. mmon m d i n t r l l i a n r c % new fmm ~ i mrobotin. d PmmAlnn ofthr Howl . soorwofmdan. M a h 119. 29-1. Hmmd. S. (1594). Whst b compuution? MindrandMarhlm, B41, 3 7 7 4 0 . ~ ~ ~ ~ d1. r(1981al. n d , Smuntir engin.$: An inrmdurtion tomind&@. I n I.Haupland. (4.). Mand hnp.Omhedge, Mh: MIT Prlo. ~.ugdmd. I.(1981hl. Thr narurr and plauihllity afmgnitivism. I n I.Haugelmd Id.]. Mind M.Cambridge, MIL MIT Pmr. Y%281. Haugrlmd. 1. (1985). An+&! I n r d l i g n a i h r Vr). ldnr Ombridge. MA: M I T P m . 11, Cam. Hau8chnd. I.( I W I . What ir mind d n i g d In I.Haugcland 1rd.l. Mind bridge. MA: MTT Prcu. SWms h tk Hap.. 1.(1Q791. The naive phyab wnife,m. I n D. MiChie (<&I, Mim.onmniAce, uinhurgh. Smdmd: Edinburgh U n i r r n i n Prns. HF .. P. (rssi), xwnd miw ~ h p rmnihro. h b HO~ISa d R. M(rdrh F a m i Throne$o l h r Cornnmonun* Wdd. Now&. NI: Ablex, 1-36. Haw-Roth. B. 115941. On building inrrgratd mgnidrr a p t . A &of Allm NWI~S u n i 6 d mcorin ~ f r ~ ~ ~ i t i W. o nC. I ~ W s. ~ ~smolir.and . M. sldile Ids.). Conlrmphting Minds Cambridge. MA: M I T P r e H?% i dasr, M. (1961). kg and Time 11. Marqumie E. Robiwn.Tmns.1. (Fin1 publirhrd in 1911 &.I. N w York H s w r & Row. H i l o n . C.. and Sh#llir+ T. 119891. I r a b n i n g ~ m n n m b n i n nnrork. UnlvmiV o l Tomnta T ~ h n i ahl n . CRF-TR.89-3.
I.
" .
I.
me
~
~
.. .
.
.
l i l y d h l i ~ h i g . "v m r . Holl+nd. I.i l w 2 l . Fenstir dprklhrm. S*n#ifi< Am'mn, lune.6672. Humr. U.. (d.1 117401. A l i m * on Human N~N .I Orford. E n w d : Cbrrndon Rnr. H w h n b . P., Smilh. T.. Iakob>.N. and 0 ' 5 h n M. (19981. BInn lidngthmugh
3x8-r.7 .". -.
Iamh. F. (1977). EvolllMn and linktin8 f i m e 1%(481). 1161-1166. Iambs. R,lordan. M.. m d bna h l I 5 9 1 ~ lTar* . drmmpasilian i h m e w M l i o n in a modduconrrnionin anrhit.rma nc .ha md whereri3u.l i.rk capit& So% IS. 219-2%. I a w b r R.. lord- M.. N o r l m . S.md Hinmn. G. (IWII. *d.plic n r i n u m d k d pm. ~ ~ h p rmt a t i a I. MI. l a n d . M. 119861. The formatian of T n g r g6p during prchmlun: A c o f l i w d i i =ad vimamotor pntrm. k M m l Brain R-rh 19,99-116. b n n o o d , M. (15971. ?hr Cagnihn N ~ r o ~ ~ ~ o fOdordl A & W m d : B k M . lordan. M. 1191sl. Smal @dm A R m i l d riD.hburrdRrmnngAppmah I R q r I BWII. ~ n s t i tfor ~ t apievr ~ sciem. uniu,iv of aifmrnia. sm D ~ W lordan. M.. Flash, T., and ilman, Y. llS94l. A model o f L e lmrning ofsrm S~ai.ni.nriri from spatial deviniars. l a u d ofCognltir Neria&m, 614). 359-316. KlmilaffSmith. A. 119921. B v n d Molvla"ty A Ilm(opno.ral Pmg.rtlnmGp& S
=-
K e h . I.*.& (1993. ~ . n i c P a " m ' Gmbridge. M*: MIT P W . Kim, I.(19%). Ph?l~rophy o/M:hd. Bovlde CO: W& PW. Kirlik. A. 1199o. Ev&y lifc cnriranmcna. In W. k h l r l and G.Cnhvn (&.I, A compnion to w r*i &nir Oxbrd. England &M. 702-7-712. K I A . D.. and Mlglio, P. 119941. On dirtinpishing rpislcmic fmm p m i r d o n . cwitin sornrr, 18, str549. Wltim. I.. and Vm F m , D. ( 1 ~ 1 1Virual . WM O n q n p h n m n r r r # i r i qm d m n '"?re", pmres3mg. C v m l OpllMo in N ~ m b l c r s a 2,,5+lS5. , m p k s S. (em). ~ ~ ~ i ~O X I ~~~ ~ . ~ ~ BISCW. d ~ ~ ~ . y hh,A. and a n r d l . C. 11" hl.w i n and durn arulpir h a a r m g q r a m a tion.1 rimillrin, Mrrm nrunl Wt.rnl. Philasphhl P l p h 0 W . Lmdi, V. (19821. ne G m t A n m m n Caunnylidr bndon: Callin MxmiUan. ~ m g o nC. , 119891.~ n i f i ~ lift. ul C. bnsen 1d.1. ~ r n f i drlk l m m FI r ~ a v u Sludk h 'he &mnr ofCompk6b (6). Reding. M k Addiwn-Wlllq. Lmlr. D,m d Frigmbrum, E. 115921. On the thresholds of L n d d g c . I n u. K i n h (4.1, Fuund;lcie!mr df Artlfi.lrl r~l~!!;~rnw. ambridge. MA and "mnerdmm. ~ hN .t h v I-&: MITPm. m d FJrGrr Science Yublish
.
REFERENCES
196
+,I.
,"fx
( 1 9 ~ 1~.hri.ri . m d 41: me- L U U I O ~ ( ~P&,~c ~ ~hi~qhidaulr64,3%%1.
M e . I. 119941. o u t ofthe r b w ~A qullophile i . . c o n h o m .a u . l o ~ W i Phihphlarl
r0&2211). ,994. Lund. H.. Webb. 0.. m d Hdbm. b (1997). A rabat r n ~ l tod Ux&CkH swk GviIm~ b?mo~!~ru'I n P. Husbands and I.H a r m I d . ) . 4,h E u m p n 5n6-m=an AHVti01 tifi.Gmbridge, MA: MMIT F m Zlb255. Lynn. W. (1991). Hnmuncular l u m i o n d i m m e u PDP. l a W. m y , 5. S*h. dD. Rumelhln I d . ) , PltilomphyandG n n n i a & l Thq. Hilhdde. NI:Ellbum. .ca
.*'
M ~ N l w h t o nB ,.. a d N.M. L. 11990). H a - M a m m m & a d ih. n e d qr-t.tion ofeoion in spa-. I n M. G l w k d D. R u n x b (&I. Ncm,& a d h m e d o n mmry. ~ Hdldde, NI: Brlteum. M n k C 119891. A n d q VLSI and N
wm
.MIT ... Pnl. . ..-,
Millilun. R 115%). Pushmi-P+ rrpr-tahm 1" L. M.y. M. Fridnuo. and A Cluk (aL.1. Mi"& and Monk Umbtidp, MA M l T Pmr, 145-162. Milncr, L,a d Goodd.. M. 119951. 'lk V?$ullBrninin A o h n Wolfrd.Endand: Oxlard U n i v M n Rnr Milwr, D., and Gmddr, M. (19%). The v k d bnin i n d o n . Whh, 41121. Minrb. M. 1,5941. S a l V of mind: A m w to four review. I n W Clmey, 5. Smp lir,and M SlrFlk (4%). C o n t m q h t i m M i d r Cunbndgl, M/L' MMIT P m r ,
,."*-..A -,-. R N A 18%). P h m d w - c and l u n t b d i m . I n A. Maxd and E.B h c h (4%). G c o i o u ~ in a ~ , i o p . O r y S d m n word. mglmd: Ctnn&n Ru. 12,-1%. M.R. D. (1963). A damy olc&U.r m n a Immd Oldf Php'dIqy, M2, 437470. Msm, D. (1982). Viliar Sxn F n w i w m W.H. Fmmm. Mllrn*, M. (IWI). Narigfingvlth 8 "I bnin: A n w m b i o l ~ u ibn r p i d o d d lar robat r p l i r l qrrwni8don. I n I.A. MF and S. Wlllon (rb.), Fmm Aninab re Animau I Ombridge, MA: MTT PMalunna, H.. m d VawIa. F. II98o). Autopp.iai$and Cqnition. D o r d m h t , T h NnherIhndr Redel. McClulv, R N. ( 4 ) (15961. I& hrurrhland. and Their CClitin. adord. England: Bbrk. wdl. Mhlcll~n4 I. L (1989). P l d e l d i n i b v v d p - m i n ~ l m p l i ~ t i n ufor.withn d d a . I n R. Mmis1cd.h PmllrlDiMhbIdPIoc&~I~pIiitbrofirPW rhaiog~mdNlur&Iw. Oxlard. Enghd: Clamdon Pms. M d d l m d . I.,md Kaxlmolo. 6 (1986). Mechanirmr ofsentcnap-ing. I n I. McClrUmd. D. Runelhan, and P. R Group b&.l, Pamllrlhlnibuld f i p ~ ~ ~thr~ ~ti m i o ~ m~ m~r ofcogninon. r ~ ~ b n d lMA: e . MIT ~ m ~ ~ r n d l o r d Buoiu. 11.172-5%. MKIC'.~~ I .,~ ~ . m r l h a nD. . n A. 11916) T k a p p l l o l p a d W d u t n b l l d pan\\% Ir I Mlflcllmd. L). Rudhuc..nl PIX Rruarch(iroup drl. P ~ . ~ ~ M I l o n b u C t d hatvtq +xplo.oran$ m thr Vino-m 01 ('optno" i r m b n d ~ c Ltr: . htlT
M-I,
... .... ~rCon!&. G. W.(1990). Whnr Vvion n n d 6 y i t i . m L M II Pap.. p-ld at the and Yar Per+oh Leu-. BCIwum. H.F.S.P. Workshop on McGinn, C. (1989). G n n m l r e the r n i n d o d y p m b l ~ mIn l N. B l w k 0.a - 3 G.G ~ u l d c r(4r.). r Thr NONR~ ~ C O ~ Y I D YUrnbridge. ~CII MA: MIT P-. 529-542.
and
MirchcU. M. 11995). h n i c algodthrns: An anri...CanprPh, 1111. 31-39, Mitaal. M. 1 1 ~ 9 ) c . m -lution -lainh w th.mind canpkery,4(3). 17-24. Mitrhdl. M1 crut
rmn
d
r98
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h b l o a m P., bid, I.. N w d l , & uul MrCld. R IIP921. A p n h y d p i . 01 the SOAR * n r h i t m r r as a h i s far g m d i n l d i g r u r i n D. Kinh (nl.1. F . 4 . limofAmiFmIIn1dl~nc~. Ombnd-, M*: MIT P r r a X9-326. Rownth4 D. 09971. A Ih-y o f c o n u i o u n ~ a I . N. Blo*, 0. h y n . a n d C. Cozrldm (&.I, TheNowre olconnownci Ombndgc. MA: MIT Pm* 7-754. Rukn. D. (I5941 A m u n * r f & l d thmy a f u v v l ~ l u a l a n No#% . 28, S Y E I . Ruddcr-bkcr. L. 119911. lnsrum.n?d insmntiondiv, In S. St;& and T. Warheld I&). M m ~Rmmmmnan: l A -dm Oxford. Enohmd: B~lrrrll. 332.344 i F i m
.*
.
~ .~
. ..
.
YorC N n Yolk U n i m i v P m Pomnm, n. (1%71. Pmholqicrl p d t a r r r I n W. O p i u n and D.M m i l l (nl*.l. A n
Mind and Rrligion. Pimhurgh, PA; U n i m i q o f Pimbvrgh P m * 3 7 4 . Puuurn. H. 119731. Philowphy and our m n a l life I n H. Purnarn Id.), Mind. Ian."dRdi," Dmhrul.~. E"&.d Cunbndsc u n i r r n i o ha*291-HI). ": Pulnan~.n IiYW,. IVxa nr and wqmmr I n U S l u l Id R n J l m p ~ nPhr P h k p b ) ol P . ~ h d o$01~ I C ~ m h n J p .tn&nJ. 08, hrodst Unhm cr Pm, p.lnhm. 7. I O U , Coap8.!.4ien.aunu t ~ ~ l ~ amnndge, o n MA' bII1 PIN s. IIWJ meclm,,au:ln,cbra n i m d c 8- t a n osr ~ o n 3mI , , 4-37 o l l n r 9 . 4 hnonk,. I .rr:i ihr nr.lni h , . ~ o ( m ~ i u v dnelopmmt. r ~ w n . ,,U,,",', ma, , k o rWI.mnmlardR.~m ~ I I L10. 5,)-5%. Qr,"r. H. \. 0 I W . W I.",. Llndl l, w \'. 0 0uonr ("1 1. cmo1npni R&nno ondOlhn Fuork Nnr Y w k ( r d v n b u Unnrnt) P l n r I!&118
.
.
om..
..
"w Rarr.,"~ Fqaa,ionc in rh.Mirrornwtvnof~ihan. Dmbndge. c. MMIT P-2 116271. R I ~ cG. (1949). Ihr C a n p l o f M i d Iondon: HulchLaoh~ao. Wzmm, C. m d Nmamc. W. I I W I I . N e u d mrrhanhms (or farninl a o n r . a M I &. -ion. S m w , 264, 231-237. Lhank, R. (19751. Using LnmIedgei. u n d m d I N U P . 75 %hank. R. m d Aklmn. R (19771. Soipn %nr W,and u d m m d i n g . hid^ NI: Erlhum. r h k k t , M IIWOI. H a m i g h !he ~ maor conn indiihratc m-nh! Tmulrin NrumYlma. 110Il. U O a . m, M.. and Hibbord. L l1593l. H m m n t o l o p i c is thr motor mna brnd -! %8m~261,4894Y2. Wwr, 8.. ud O'Lnv D. I I W I I . *lid o f v i d mrm to dordorbp an a n y 01 functional uniu uniqw to m m l c e e w w m n a Sdnr., 2 5 1 . 1 5 i b l i M Lhbnrr. G. 11993). Whd Csn W ~ h m h a EwAnirMdrlrdRhflhmkRehdmin n. A n i d and Hunnnr?Unpuhlishnl manuwrnn. SchNdinger. E. 119691. What k tifi?Gmbndy. L n W Cvobridgl V n i v ~ P-. q slrle. 1, (1910l. Minds. b r u n r m d pmgnrns fihnnmal andBrain Sows 1.417421. w n n r d in I.H a u y l ~ n kd d ) . (19971. Mind %p IL O v n h n d ~ England: Ombridge U n i r n d y P m % 16S2DI. s l d s 1. 11992). 7he R d i m v @Ilk Mind. Umbridgl, M A M I 1 Plnr ri-, T.md R ~ m n t q ,C. 11986). NETmItA Pm&IN.MIL Tl.UmmW R d Aloud lTxhni
..
.
my. 1'.(1991). An approrcb 10 the qmlh4sollifc. I n C. lmgton. C T q l n . I.Fmrnm, and S. Rvmvacn (4s.). Anifi<;d ire 11, R d d Civ. U:Addbon-Wnky, 37,m. Rsy,T. (199n. An d ~ ~ i o r approach u v i.synthnt biolow a n and the an o f c m t i n g lih.Amj%dl.Te, I.L7%2!0. nrrke. c.. and Eddmm. G . lI98Bl. Real bnins and ndmeidintcUigncc. cedaiu$ Winhr .., IILI11. mnkk M. 119%). Tc,nlr* Tmn;m and T.lfu l#nc Evimlions in Masiwir PanlId M ~ m Ornbndy, r MA: M T PIru. ~ml& FlorXr. herds and uhmh: A distibvfnl behav+R1 made1 (bmpum . C. 119871. . Cmph* 21. Idy. ~innl~G t t ,~Fadiga. . L. .nd Fogrsi, L (15%). ~ a o connand r ihr r e a p i t i o n d molar actions. C w i # i wBrain R m r r h . 3. 131-141. la,A,, Pdiu.5.. Wn.I.,mdSur. M. (19901. A m ~ p o f ~ v . l ~ ~ i n d w d i n ~ n d i lowvxtex. Snmcr. 210.81MM. noxh, r. I I*). 1%a u d , w C O ~ ~ I LO , U ~ ~O~C-WWS ~ Stwdsth I(II. -5 R W " C a m P.. and I,,d. I. l r P i On ~"0h.dh m n u o f < m .,on A mpxu l o h e ~mr~ant~.,r,i4m,t. 59. I W 413 ~~~
.
'it"
S4nouaki.T.. and C (19871. P d c l na.mCr #hatinm to p r o n m Enp l i s h t a C m p b S ~ m I, r IlsIM. Sholmakn. 1 (19811. T h e in.*& r ~ r u m bwnd . ofPhibmphy. 7117). 357581. Slmon. H. (1%91. Thr arrhit~currof c o m W v . I n H. Simon (d.1. TkSdrnm a l r k An?fi&l Cambridge. En$lmd: Ombtiduc U n M Q Prnr Simon. H. (19821. MddrofBovndd Rdtianiiw Umbridy. MA: MIT Pm* V& Imd
...
S m n , H. (19961. I l n S n u o f t h e A m j ? ~ l O r d(dl.Ombridge. Mh M" Frrr. Slurdl. c.. md F m n w . w i ~ m HOW k bnuv & d i n ondo to makc v-a1 t h r w r l d . B~h#lhmlondBmin Srimis la 161-IW SIC?, j. 09801, 1ndiridu.l d i h r r n c n in 6.d i m l g q ahlUq and Ulr mri.4 ofV33llll *-nrr. JournnlofMmcol l m q q , I , ~ S11. I s ~ n r.119~91. . r-tims a d b n b prmeua. ~ h r ~ o r m h a ~s. ~ ~1.1-I%. n.,
101
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INDEX
m&,,
" .~n.l~"io" . Awe, P.,
of
132
Aileron p"ncipk, IM
AUU, K.. lea - ~ l i ~ m 8 t i a nlniwn). . 2%17 1 ~ ~ h . i ~wtimtr. ~. and homcentimn. m e l r 157 Ambiguous i m a p . 11749 *mi,. M..2 A ,*I,. ,nu. nnlhav u.nrfo-uionr in ~magm.I49 hti,ryr-tntion.lii 1%12. 110-39.. 3SymbIii am. f . . nmn~nutiow , ,<,a1 ~"tdiigmrr Arbib, M , I I Armr!ron& D.. 1% 184 /uuT,
.I,.
A n i m a l n a r d n.t.o*. 5 3 6 6 2 4 3 .nalyis of,6b70.75.76 hinindcrl din .~.~ ~of.-7-1 and bmin. 62 and chimar Raom, StnA ~ ~ d i n u o l dmr l m pnrY11 in. 72 d,&bufd qnwnution, in.62f64 and d ~ a m i c lsyrtmu. l 120. I W 3 l pxing in, 78 ihrminp dporithm tn.63.65.66 ."d m,cmfunaionrlum. ?4 noiw m. 72 psy
m c k ~ p w g a 6 o nh l n g , 63.65,66 Ward. D.. lOnd, 91 m"
INDEX
21, x . 174. 1 n d 1 . 187 Boden. M.. 117 Boa!=. G.,9 Bouchec I.,I59,188 B o p , I.. 144 Binddon-Mirrhdl. D.. 49 Bnin. I 3 rnd m i f i d ul.1 Nnlh.6 2 . 7 9 4 2 8-496 b a ~ k ~ p r o k opslhwy5 in~ bin 8 w u bagoltri&.3MI. IW and ragniav
BI-~.N..
Ormkm L. 159,1111.108 awtraph'l loanliym, 81 omtion, .ount~rfartu.l auounr of. 55.
u ."
OUW, and connmbnirm. 7h76 mentd rt.tes q 1>16.57.7>76 and p r w m crpluutian~.57.58 umrred, s h % Chlimrr?. D.. 17.1% 22,23.77.154, 159. 175, 179-83. 18S-87 C h a m b ~ D . .I I 7 , l l s Change bli"d"ns91, 102 Chmnpur.1, I45n.l C b a " ~ 1 Y. l C.. 16* Chimps. 14445 -Chinew ROO". thou*, aprimnt. 34-37 ch~nrhland,P. M.. 1. Y n l . 35. IOn.8. ,447. Sl.53.55,56.58 59.68.75. 76,1111. %91,92n.9,93n.lO. 164. 166.
I Comny, 1.. 52.53 Cor.& i L.40 Conrrll, G., 7b b u p l i n & 121.12~23h n l c o D y n m i ,p,- lh-Q Crick, R. llS.173.IMI cu1ruic, 153. . k o h C o ~ o g i ttnh-1. i~
Bumn. T.. 25 ~ l i n d i & +I72
"..b,
mind
cqni?hrch.bilitatan.
.,
157
Cognifiw twhonolw, 1-59 m d mgnikivc dosun, 183.184 iomPlemcnting the brain. 142. 1%
Computnion in Deep a ".. a d
cumm"i,. F.. an.1 C,brrnn,c tunlrr lo3 Cyhrrpunk 156 cybaw. IS%% NC pro*,. 37 D*masia h, 101. 134 177. 187 mmuio. H., 101 Darirr, M.. 187 Darkin% R. e4n.z De'on.T.. 151. 159 h r p Rlur. 20 Dchamr. S.. 78 nmnm.D.. 11.11,(6.47.4%Y. %".I. 5% 18-60.78.79, 66. 101. 143. I U . 151, 168. 170,176. !7&81, 183. 1%
Evolution an16od. 98-IW u ,n<mmmld, e6 1 .nd iupple adrp!=tbn. 117 as tinkering. 66 ~ m l a i o n w ,p~~choIow.Ul E U V~ ~ approrimna ~ s mkdntbn. ~ ~ 146 Erw" .&dl. 37. 38 ~splqnatnon,wnur k d p t b n , 122 h p l m n o ~ g . p . 175. 185. S n h h I
,:,",
. ... >
.*
FOIL ory~halap SnPmtitionrl
mi-
8li*m and iunuiownm, 21-25 p m n a 10 m k m f o m d *em5 )6 mulliplc xaliubiliQ of, 39 Fnnilin,I. I 3 . W . I l b 123 Frmmm. W., I29
neural iorml=ler 01. 175
~ a , , t ~ t . &O ~~pmalstinm.;h n xir, b.ptr.rml a.zrount3 01.49 broad vmut m m . 48.19 nvr.1 thmrionf. 49
F q < . U.. 9 Fundionll'bm muhinr l~nrtiond'lm,11.164 169 mirrohmrtiondiun. 36 and qudia. 36
Edclmul. G.. 82 ~ r ~ i ~m ~ att O i ird 1 r ~ I-. . 56% 169. I70 "iminl,irirm. sa nimirut1n m.t.r*l'irm
G*llmf. I., W G.m.of Lih. 52Garon, 1. 7576
G ~ ~ M.W .13% . in Gmaic almtithnu. 9 8 . B Gihwrn. I.I.,Yin.13 Gleick, I.,24 Globd d i n i p a t k rR*N 1WIO2 GWour. F. h . 1 Ccdfrey-Smi6.P.. 118 Gmdalr. M., 1)6311. L7L74 ~ ~ d ~d cn rnm lf learnin& 65 cr.hlm.c.. 170 Grase, P. 104 Grurh. R. 131 G u r z l k , C., lM.187
H*". H., 122 H.drmlaion, 9 b l W Ham&& 5. 11 Halvnl. I.98n.16 . flaugdmnd, 1..8h1.9, 13.23. Y. 159 H q n . I.It".,. 29 H a ~ R o t h R., . 38 Hszrlhun,. R., IS, H n d y r , M.. 37 HcUm. P..147, 149.50 H~.IX.~(.&I. 91-92, Im Hnbhard, L. 87 Hi8hcr lml copition. 129.13U9. 140-59 Sn oL.Nannami~ propnirr. symbalic anifirid inteIIiBrnBrnBm ~ i g h r ordn r rclarionr, 14-5 H i e c r ordn thought iheoly. 176. 184 Hinton. G., 68.71. I42 H i p p a l m p w 81 ~ ~ l , , ! i rsijnilaritl rrcoglitian, 37. % a h . ( n ~ B < rnruml l "nm* Holland. I.,99 Homunruluitf, 116 Honrunt.1 microworld%79 Hun>r D.. 885 numphria. G. I87 Hushsnd* P..8I.98n.16. 101 H v l i h # n rE.. 141. 113. l53.I%
l n r o m t i o m l phmomn=. 11 lnmr s p h o l flight. 5.73.120 Intmnond stane. 17. -53. +59.
,7*
m.SnFormd I&; Formal m ~ m s 86.
lang multipliut~anexample. 142 Lor dimenrionrl d n d p i o n r . 121. S n
Mtclpucviaual w m , 69.90 rim l n l n n n P I Sorrr. 1 ImrmpecUoh 164-65 Inwnmg I<-. 87.88 IxtmdoU, R.. 9% 147. 159 I~c F., ~ 49.57, ", 1m.b. F., e 4 lacobs R, 78.81 I-nnemd, M.. 173 l o r d m M..68.78. (11. 133 KumlloA-Smith. A. 80 KmuAmsn.S.. 118 Kawamola A,, 67 Keifmc, F., 110, I29 Kdm, S , 87n.3, Bt3, l l 6 , l Z l , I22 K h r p m imlmtl. 107 K ~ ~ . I . 12.n. . 1n.176.1m.181 KklSk, A, MI Kirrh, D..42. 141. I58 Kmrrim, I.. 89 Knowng-how m d Lno*ng-d.l. 37.1 Kwh.=., 173.180
Lngton. C. 108 hnguqe,
ad e i l i v r ml+ 14447. SII
aho Highn 1-1
iopilioni S a b l r kaky*rsntm,, 1-1 k i b n i r G. w., 9 Lmbnii law, I 6 7 4 k V a p S.. I55 kvell of dewtiption o1b".in, 29 in 1-ky mtmr 160-61 M m k -6. % o l o r w i u t i o n in n a u q l b l 9 m n . D..102
I.,175,183 ~ i f em d mind lmmpmd). 117-19 Linsuiair turn. 165 USP. 13n.2 Llttmm. D.. 153 kne,
Monism. 4 M o n h y finer motion. MA7 Mulliplednltr. 178 Mull>olrrelliubility. %krmal Vtemr;
Machin< funclioniisn I* Funrtionllirm Madio, P., 141, I58 M&r. U., 84-86, 96 Mllrtir. M.. 93-95 Malunn*. H.. 117.129 MrCaulcl. I..64n.l ~r~lam&k.,R.. 119 MICldland. 1..67,6%.79.81. 142 MiDondd. C.. 77n.I h4iIlonnld. C.. 77n.l. 113 MiGinn, C.. 183 McLrugNin. 8.. 61 M n t machine. h d n u, 7-8 MCrn0.y
rnrrnd. 141, 112, l4%5O. 1%. & a h c o m i t i w ,eChno1aw
Nolm. S.. 81 Nolfi, 5.. 113 Nonconeptud mntml. IM Nnnlinor funrtionr.61. 115
..
N o m n . D.. 39, I43 ~ u m e r i mmmprexe, l 116
...... M~lrhalYm,117 Metahad pmbhn.of
Odm, D.. 144
o r n d i so, ~ 102. ~ n . b c o p i t ~ w rwhnology M-w. cnnn.1 O'Lzw-HaWhorne. I.. 6, Omni (maguiml. 25 pardltl d i n n b v t d prmryin& Sn Anifi"81 " c u d nrnro* Pnnllrlirm. 163 PS",C,
D.,$5,
P ~ T . I.. 19 P3"l.l Pmgrms 133, Pnxnl. D.. Y humon. K. 68 Prs-k<. C., 187
In
INDEX
.llroConwiawnar P d c r , S. 149. I83
u.
PI*<.. 2. I t 4 Plmning, 92.9-5, la) Plunkm. K., 79 Pollack. 1.. 7717.6 130 Poppr. I(.. 181 Pon. R.. 68n 1.72
R.7, T.. 117 R n l pammr 14 51. 5 L 53.56.57 Rnlbm. 64 Rownr. 2.4. S1e ahI.R.dandily; Repre wnurion.: S","bolt irtr6~ulintrlli.
gmrr
m d m i K W tik 119
--
.. ....
and compulrfion. 15-16 131, 13s Rccunrnx nm.ork69.70-72 k u n i r e auto a s x i e l i w m r m o ~ n , ,78 R<*I, C.. 82 R t i h D.. 117. 148 nrprsmtatlan-hunglpmblpmblm~ 110, 112 n q m m t u i a n r Sn.l',A",irqram". son.1ism; S,,"bal~
of. 48.49 distributed and ruwrpoullan.l. 64 67. con,.","
,,,
ob;mlvi$tmu i d & a - l o b & n d .
W u 171.172 Sn&CoMooumar Qualilriw q r i e w r . SrrConwiousm~ QmrE. 5. 152 Quine, W.V.. 19 RMM. n-78 b d i d e m W mpitian I28 bmsrhmdnn, V.. r b A , 88.5U92n.9. 93. IM W. 7%76 Rat. m u r "m.+@tion 0L9N-95 n n o n d i v , 16.4,. S n o b Hlgh" &I
w,
"W
I3143 puhm;pdp.95n.ll lr r x i for ~ d o n , 84,914, IM spti.1 purpox. 106 ruboymbk, 67 hprnmtationd The, olMind (RTMI, 43 Rep-ntstknlrm. 175,!Isr Rqrewntationasa m p i m r scimce, loel2.I3., I35.Sn.bRxprrpnmtion4 Throw ofMind: Svmbolic mifi-
mnd'mnmtiailm, 82 u " " e y l t . Y"., Rumclhan. 0..79. 142 R w U . 8.. I)
nflr, c.. 165
S d a ri.u.l.91 SnRbldim ccpiliur. 157. 161. Y1 aka C g n i r i n lrrhndw Wlmk, R.. 30.31. 35 Sch!h,hr. M.. 87 khrddinnr. E.. 117 ~~
~.~
.
~
~
.
Snrl.. I.. 2,-23. *37 *idcnkg. M.. Icjnomh.T.. 17.10n.8, 63.61,70,CQ,81. 82, 84 Po, 91.92h9.93. %. 97. IS2 Iclf b u n & of, l K 5 8 "<""I rrpmm,.tim ol.In Wf-oryniuli"n. 113.111. 118. S n a b m i 6 W l llir Dvntmiusntm the. m;nohotiu Sananl~rallyninrpurnt sptrms 29, 33. 35,,,,97
Smmn.~., 116 Pi&. S. 73-76 st,gm<*c andprithmr lm-9 Strang mnlinuiQ, oflif. and mind. 118. 129-31, 150. W 01s Copitive k r e m
~
,,kcid ~ "Wed om,!., " S u p r p x i a m ~-din& l 66, 67 supplr rdlplfion. 117 Spbiods af b r a i and wr!d SI.Cognltsvc tcchnologj Synbol. anific>ali n t d l i p e . 7-16.19. 2842, abo I c m . n t i q t n ~ r -
*<
" Isync",,
b n m . k d rritiqu d.1 w 1 0 2 and connrdionilm. 66,67,7&79 c v ~ ~ r c o p ; nupp m b l m lor, 57-38 SOAR. 8s rumple o t 31. 12. 100 Svmbolr I. 15.2s. S n a l l o S m b l i r d.
m d connmbnirm. 67.73,71 L I . I - ~ . 17. ~n.bs,,u. d l n i t i o n of. l o i" "Chinex Raom. lhovgh, e r n , .
rmankiir.
1C37
of cronnmioni* e n d i n g & 66.67 I c n ~ h i n k 4 0cyrlc. IUI Sh~llice,T., 68 Shnr. 1.. 187 Simon.H.. 8n.l.9, 13. I3n.L 28.29.31, 33.41.86n.2, 131, 158 Simon%D., 102 sin*. C . 79 SLS*. C . In Sbt~hing,11749 smm. I.I.C.. 34, l(d Srnhh. 8. C., 85. I I b . 4 Smah.L. l2On.l. 124. 128. IT). 132 Smllhen. T.. 129 S m o l m r h P.. 67.77. 1 4 som. n,32. ~m, ~n olmsynrbo~ir a n i f i d i",rlligen
.. ..
mnnmiooisc, 64 67 drfi"ili0" or. 10
T C ~ W .p m l w n
T m n i n M,buildin& 103. ! O M Th.
210
A 1 11 566658 mo"shrr.boul-thoushu 2 . l l c 1 7 mo Lemnn. C,147. 11>10 T k k n n rids Duslon, I37 i'arda. P.. 117, 129. 132
TIWpm*n. 117 Timing. 97
Ventral*rcam, 1%3%, 173, 174,
Tokens. 9.10. S n e b *rmntio; +ry Twby. I.. 10 Toribia. I.. 110 Tr=admill rtrppiw 1 2 e ~ Tnnnl%fyll~u,G..I43 Trianl~frllou.M I43 ~uinq:~.. Tuna. 143 Tun4 fih- nmmr u.89 Tucing. A,. 1-11.21 T"ringm.chin.. 1%,2. I,, 169 cnmplr of. 12. u n i u c d . I3 Turing Tat, 21 TF. M.,175. 1%. 187
iGi
~
INDEX
~~
Ien
I..
vmtijnm. 147. Virusill -hi04 29 Viruomo!ar mion. 13638 *on Ne"m.nn, 1.. 11 Wdtcr, W. G. I03 Wulidd. T.. 75 Wlrw?ck. K.. 156 WIR 8 0 V m r . 125-Z& 130 Webb, 8.. I(U-7 WdskJantZ, L, 172 Wldxh. 1.. 158 Wheeler, M., 72, I29 Whirchmd, A. 9 Widcrrrr. Zu W i x i w I ~ ~ D O W 8s
.>
a<
World, as R. own k tmod4 M). 91
D..78.89.
101 nn Cel&r, T.. 71. 77. 77n.6.77n.7, 120n.l. 125-28. I30 Van W n .
(XL
ZOmbk23. 174,18142. 115, 187. Sa. aluc o w i o m ~
